I can figure out how to play the game Roxlimn; I just keep finding mechanics that I find annoying and not-fun. Yes, I can raze cities and replant them with settlers to avoid courthouses. I can plaster trading posts on puppets to starve them of hammers so they build random junk slower. I can use magic maritime food to pop insta-cities. I can micromanage population growth all over the place because of the idiotic global happiness cap, and I can mint happiness with buildings once my empire has critical mass and is making cash.
All of these things reflect poor design, and I keep running into reminders all of the time. I can't partially buy things; I get chump change when I lose a race for a wonder, just to rub it in my face that I lost (but I can insta-buy anything else anywhere with cash); I can't control passive growth of my cities and the fool algorithm hates hills and forests, both very useful, and it makes them extremely costly to buy.
There are just plain bugs in the current diplomacy. AI's plant cities next to me and start unprovoked wars because "our close borders spark tension". AIs that dogpile me with chain-reaction declarations of war. AIs that brand me a warmonger, then attack me, after I join them in a war at their request.
Your points about military buildings and so on would be well taken if fighting was interesting or fun, but it's just not a tactical challenge. I'm either stomping the AI or on the receiving end of an ambush (which usually just means I have to get peace with one AI to wheel back and crush another.)
1. Getting cities from war should be a trade-off between just plainly settling it and keeping what spoils you get. There are plus sides to annexing, puppeting, and resettling. Currently, puppeting has issues that make it much too effective, but it shouldn't be crippling to simply annex your gains in turn.
You may find this annoying. I actually like this as it makes keeping conquered territory a strategic decision rather than a forgone conclusion.
2. Maritime food is an attempt to globalize food distribution in Civ V. It's much too effective in the latter eras for small cities, but this is both good and bad. It's not much worse than Sid's Sushi in this regard, in point of fact.
3. Global happiness caps theoretically put a cap on Civs so that smaller Civs have a chance to compete. In practice, it's more like barriers to growth that can eventually be surmounted. There is no need to micromanage population growth. You can broadly plan your cities so that you have just enough cities to reach plateau level (about size 10-ish) at your current projected happiness resources.
4. Partial buys I don't get, but I don't see how this is necessarily poor design. You have to buy everything whole, or build everything whole. It's a limitation on the power of gold, which is powerful enough as it is.
5. Losing a Wonder Race should cost you. In Civ IV, the gold return was equitable, and it wasn't uncommon to build a wonder for the gold return on losing rather than for the Wonder itself. This is good design, not bad design, since it follows intent. Losing a race shouldn't be good.
6. I don't see a problem with the Culture Algorithm making valuable production tiles more expensive. Generally, things that are great should be expensive. It would make more sense to make getting to luxury tiles even more expensive than getting to hills and forests, but I'm guessing that that would be bad for strategic placement.
If you don't like paying much gold, play Washington.
7. All the Civs expand and want to carve a name for themselves. If they settle next to you and then send messages about not liking border tensions, then the resulting war isn't, in fact, unprovoked. THEY are provoking YOU! I don't see anything wrong with the behavior, to be honest. Did you want Civ V to have pushover Civs?