Thanks. But you probably should've read the rest of my post first.
I did. You didn't address some of those points nearly as well as you seem to think you did. (Besides, it was a comprehensive list of options, obviously some of it would be redundant with things others had said already.)
First, large empires do NOT shut down SPs, because the +30% is additive instead of multiplicative. So as long as any new city produces more than 30% as much culture as the capital, it's a net gain to add a new city.
If your empire is rolling in wonders then sure, it's hard to reach that 30%, but if it's not? If you've only got a handful of wonders, then the 5 culture for Monument+Temple starts to add pretty significantly to your empire's culture, and easily offsets the increased SP costs. (Especially if you're France.) Sure, rushing a Temple sounds pointless, but I've been playing Egypt, whose Burial tombs are +2 happy +2 culture, and THAT is definitely a worthwhile building to rush immediately in any new city (border spreading and happiness boost in one!). Before that, I played Persia on an archipelago map (and lots of water means lots of money and very few roads, so my income was huge), and I'd rush-buy at least four buildings in each new city.
Second, stockpiling. The question becomes, are you actively expanding at the moment, or did this come up on you some other way? It's often in your best interest to save up some culture points to buy the later-game SPs as soon as they unlock. (In my last game, I bought three Rationalism SPs as soon as I hit the Renaissance, resulting in a massive science boost. If I'd spent those points on lower-quality SPs in earlier eras, even with the reduced costs I would have faced at the time, it would have raised the later SP costs up even higher.) If you've been steady at a given number of cities for a while, then it's likely that you're either at the amount needed for a new SP or close to it.
Using a statement that begins with "Barring trading for more resources" is hardly a slam-dunk, because
that's the main way of dealing with unhappiness. ("Other than that, Mrs. Lincoln, how was the play?") No, most people don't trade for every possible luxury at every opportunity if they don't need to, for two reasons.
First, because if you're at +5 happiness, going to +10 only really makes Golden Ages come a bit faster, but if you traded a critical luxury to your opponent to get that boost, he'll get a lot more utility from the trade than you will. So trading for more happiness when you're still in the positive numbers isn't really a good idea.
Second, because if you're talking about city-states, it's an ongoing cost to keep their relations up. (To make things worse, what happens if you spend 1000 gold to get to Ally, only to have another empire conquer the city-state?) So if you're running low on cash, is it really worth spending that sort of money for a happiness boost you don't need? Or would you just be better off using that 1000 gold to rush-buy a Colosseum in one of your cities instead?
End result, you'll often have some way to get a new luxury that you won't take advantage of until necessary.
Indeed. Will not help. When you're at -15-20 Unhappy, this will take forever to matter and/or may eternally cripple your cities.
Not really true. If you've got a 10-city empire, then starving each city by one size saves you 10 happiness, barring any discounts for certain SPs/wonders. This isn't really a good long-term solution, because it takes too long to recover and the loss of income hurts badly, but it's at least an option. It's especially useful if you have no intention of recovering; for instance, if I'm ten turns away from a domination victory, and I just need to keep my people happy enough to avoid the -33% penalty, then there's no downside to doing this. It also doesn't take long; spend one turn not farming any tiles (all specialists!), watch your city shrink, gain a happiness.
Not just raze a recently-conquered city. Raze 90% of cities upon conqering.
Hence the "or wait for it to finish dying". But I disagree with your 90%, and your own culture argument above is the reason why. If you're capturing small border towns that have never had any culture, then sure, burn 'em. But if a city's had a lot of culture and/or paid border expansions, then the amount of territory you lose by razing can be huge, and it's often worth the 5gpt (and Courthouse building turns, and lost turns of rioting) to keep all of those hexes, even if there are no new luxuries or strategic resources within those hexes. It's hard enough getting a decent amount of culture accumulated for SPs, but if we need it for basic border expansions in the late game as well?
(And obviously, don't raze anything with a Wonder.)
If you are building stuff, you are not playing optimally.
Now THAT is just a dumb statement.
Some things should be bought, sure, but money is often in tremendously short supply in the later game. For the cost of a single rushed Colosseum, you could enter two research agreements, and that building might only take 10 turns to build the old-fashioned way. Or for that same cost, you could upgrade three or four units to the next tech level. It's a non-negligible cost to rush something that big.
If we're talking about a newly-conquered or newly-founded city, then sure, buy it because the city's production will be nonexistent or better used for a Courthouse. But if it's just that you never got around to building that Colosseum in one of your older cities because you had more than enough happiness and didn't want to pay 3gpt for something you didn't need, then it can easily be better to build it.
*I* never got "that horrible unhappiness level".
"You" can be both singular and plural. In this context, the "you" corresponds to "anyone who's having massive unhappiness problems". You don't have to be using the ignore unhappiness strategy to reach -10; an excessive conquering spree will do nicely, even if you're razing regularly.
For instance, in my most recent game, I started on a continent with three civs. In the ancient era, two of them declared war on me at the same time. Thankfully, I was Egypt, whose chariots are awesome, and I wiped out both of them (although it took a LONG time), razing their non-capital cities and capturing the capitals.
So far so good, but the third civ on my continent, Siam, was at 9 cities by the time he declared war on me (industrial era), at least 5 of which were well-developed, wonder-filled cities with huge culture. So when I started conquering his cities, I couldn't afford to raze most of them. (Replacing them would have cost me far more in the long term, especially compared to the other civs on the map. Rome and England had gone on massive conquering sprees on the other continents and were now racing me towards the spaceship. I NEEDED the science and gold those cities could produce.)
So, I had quite a few turns where I fell below -10 happiness, especially if I'd just conquered a new border city that I was in the process of razing (since the conquered unhappiness doesn't go away until the city dies entirely).
The mistake you're making (& the OP is making) is generating all that Unhappiness & either ignoring it or seeking greater penalties for having it. Raze. Raze. Raze. No unhappiness. No "solutions" needed.
Clearly you didn't read the OP too closely, since you completely missed the point of this entire strategy.
No matter how much you raze, you're still adhering to the game's core limitations. You're trying to keep your people happy, and slowing down your empire's expansion to account for this. Sure, you can raze a conquered city, but you won't get anything out of it; in terms of money and production, you'll be exactly the same as if you'd never conquered the city in the first place. If you found a new city on that spot, it'll generate its own unhappiness, forcing even more rush-buying of happiness buildings, and it'd be quite a while before it would be productive enough to contribute significantly to your empire. This slows you down, keeping you from going on the massive conquering spree that was the bane of earlier Civ games; in Civ 3, you could conquer an entire distant empire in a turn or two (in the later eras, I mean), plop down the Forbidden Palace, and suddenly your empire was twice as productive as before. Civ 5's happiness mechanism attempts to limit this.
But with the OP's strategy,
you don't have this problem. You conquer, and just keep conquering. There's no reason whatsoever to hold back. The cities you conquer are just as productive as your ones back home (once they come out of rebellion), assuming the appropriate buildings are in place. (Rush a factory instead of a Colosseum, for instance.) The only limiting factor on this strategy, normally, is happiness, and the OP's point was that this was an inadequate balance.
Compared to your raze-for-happiness strategy, the OP will have MUCH higher science, gold, and production, because those captured cities will contribute far more than any new city you'd found on the spot after razing. All he'd lose is city growth (which people trying to keep cities happy will limit themselves, and freezing a captured city at size 5 still puts it far ahead of your brand-new size 1 colony for a LONG time) and the -33% military strength. And that's not even mentioning the financial benefits, like not paying 3gpt for each of a dozen Colosseums across the empire; that adds up quickly, and the cost can be used to make more units. Or like how if you don't care about unhappiness then you have no reason not to sell the last unit of each luxury within your territory to other civs for even more cash.
What we're asking for, then, is an unhappiness penalty that makes the latter situation more like the former. A production and gold penalty for unhappiness that makes empires with massive unhappiness less productive than if they'd followed a strategy that attempted to manage the happiness the normal way, because ANY attempt to manage happiness (even your Razing "strategy") will result in less production, gold, and science than the OP's method. (Especially far less gold, which is the major limiting factor in later ages.) And that's bad.