You want to provide some links to these supposed posts?
Well, besides the many duplicate threads on things like leaders and one-unit-per-tile which constantly come up, some other discussions right on the page include "Spearmen vs. Tank," "Domination Victory" (directly copied from Civ Rev here) and "Immigration and Trade" where many posters are proposing simple/one-rule fits all systems. But really, what other people are arguing doesn't matter too much, it's too late for such ideas to make it into the game, that I'd agree with.
Several of your next points are very wrong though, and I can offer several more examples - removal of tech trading, possibly lack of transparent/understandable diplomacy with the AI, and altered victory conditions being a start.
substantially improved combat
Substantially reduced combat mechanics. Removal of full navies and transport ships. Removal of city defenders. Removal of promotions. One-unit-per-tile limits. I'd be pretty confident in saying there will not be a significant increase in "strategy" compared to previous civ versions - where economic management, stack composition, and more were, in fact, strategy, even if you didn't think or like to use "strategy." At best, the system may allow easier exploitation of the AI, I'd give that point, but not necessarily create any better combat experience for the game. And on larger scale, micromanagement would certainly be crazy.
Also, this is a *good* thing, because individual units & good strategy are now much important than the uber-simplistic stack-of-doom
No, again, you don't really seem to want to acknowledge what "strategy" is. Sitting one unit at a chokepoint, maybe an archer or two behind it, which the AI could be too stupid to overcome, isn't any more "strategy" than building a well organized force of siege and cavalry etc... to conquer enemy cities and countryside. If promotions/army concepts are removed, city defense becomes almost automatic, and most empires don't have many units besides those that would sit around at chokepoints - there's not necessarily going to be any more "strategy" and could very easily be much less.
via such things as limited strategic resources
Yes, with removal of resources and resource types, and reduced management on city-by-city bases of happiness/health or your general citizens' well-being.
Civics/government types were removed, espionage and some side-mechanics seem to be out, and religion was removed - nothing is really gained here, it's just an altered system. Losing religion alone is a pretty large blow as one of the great successes from civilization IV.
truly *unique* civilizations
Fewer civilizations. Removal of additional leader choices and leader and civilization traits. We're unknown on how the AI will play, it may or may not be more heavy-handed and hamfisted than before - where AI leaders are just too pathetically predictable. Again, basically just replacing new things (unique units/social policies/wonders for each civ, instead of old leaders, leader traits, etc...) but not really any particularly new developments.
giving players greater control over their acquisition of tiles for their empire.
Removal of culture mechanics. And for someone complaining about annoying "complexity," I'm not so sure you'll be happy to hear about or perhaps be one of the players annoyed about having to individually "acquire a tile" hundreds of times per game - that really is tedious and step back when you think about it.
I do recall similar accusations being made about Civ4 maps
You're just wrong about this as far as the facts go. Civ4 had smaller maps - it had a lot of other great changes and mechanics, but the game was not designed with the best balance or actually realized on larger maps. Sure, maybe you enjoy smaller, quicker, and simpler games, and that's fine, but any realistic poster would agree civ III had a larger scale to it, without any mods. But disregarding III vs. IV differences - it's obviously true that Civ 5 has introduced a half-dozen things that will make larger/longer games cripplingly annoying to play - individual tile acquisition, unit bottlenecks, and altered diplomacy to start. And really, I'm happy waiting to release to see what really comes out, but there's not been a shred of evidence anywhere of anything but smaller and quicker maps.
the predictions have proven to be utterly unfounded. I believe your predictions fall into exactly the same category!
No, I'm pretty sure my predictions - some already all but verified really, are right on the spot. The really easy ones could really just see later posters point and laugh at those who disagreed - like the size of average maps/gamespeeds players will play on, there will be a clear answer there. Stuff like the combat system will probably see heated debate for years as after all we still see civ III and civ IV fans duking things out over various changes. But some things - how chokepoints/bottlenecks and exploiting the AI work, how exploration, navies, etc... are handled will probably be worked out - and don't blame me when either the answer is more annoying AI cheating or the AI becoming more of a pushover. We really should know what we're getting, civ 5 isn't another Spore at the least where so many people were so overhyped and disappointed. Again, I stress it doesn't mean the game won't be fun, particularly to those who agree with every type of change, but certainly it won't be the same as previous civ versions. And yes, everything does revolve around a few core factors - making a simpler game in most aspects that in the end they want to sell to as many folks as possible.
And back to the OP, since you and others were still missing the point of many posters I guess - I think it's a rather clear answer. If they want more people to buy the game, they should actually, well, make a better game rather than firing employees and shifting the brand to new products or whatever. I think it will sell well regardless because they are aiming at newer markets if you will, but if it fails it's not a big deal and certainly not a big problem for PC gaming.