Little Willie may have some serious personality issues, but he is at least in the ballpark on one thing as much as I hate to say it.
There are a couple different game plans that stand out as clearly better than the rest. The game is just designed to reward players that play according to those plans.
For instance, having a lot of cities is really good in this game. The AI picks on people that are the lowest on score first and the buildings inside cities add greatly to your score. Lots of cities times lots of buildings will keep the AI off of you even if your army sucks. Army just isn't given enough score weight in relation to the weight that buildings have.
The takeaway from that is to try to expand if at all possible. Plenty of things reinforce that. More cities generally means more research, more money, more mana, and so on. Having more of all those things helps you win more.
Additionally, if you have more cities then by definition the enemy has fewer, and keeping the AI from expanding everywhere is another way to keep their score from getting out of control.
So clearly the game actively rewards having lots of cities and actively punishes having few. It doesn't matter which race you play, you should generally try to have a lot of cities rather than only a few. That part doesn't change based on what race you choose. The race you choose will make a lot of the micro things getting to the end result a little different, but in general the same macro is going to remain in regards to expanding your empire as much as you can safely do so.
Research wise there are really only two serious macro plans. The micro of exactly which order you research things in may vary slightly, but the macro of your overarching goal is probably not going to differ that much.
The two plans generally are, 1) Research the cheapest stuff to get the most number of useful techs the quickest, or 2) Try to beeline straight to some powerful tech and abuse the heck out of it before the opponents can get anything that can remotely match it. One of them is going to be a jack of all trades and the other a master of one. The one that is decent at everything will try to use its versatility to counter the raw power of the other and vice versa. There isn't really a 3rd plan here.
While I may defend one of those plans over the other, I would definitely say that one of those two must be the best. Every player probably uses one or the other and they might switch between games, but they probably don't use a 3rd strategy.
The implementation of all of these and other overall game plans will vary, but at the core there are a very small number of strategies that are rewarded by the game and everything else is clearly below those when it comes to end results.
This game is better in that regard that most of the other games I have seen, but it isn't the utopia of gaming that little willie and his ilk are searching for. In dreamland where he lives, a game should have 20 or 30 viable overall strategies and if you selected two randomly and pitted them together the win rate would be close to 50-50 with equally skilled players. Also in dreamland where he is from the AI is somehow programmed to think equal to or better than humans can.
Maybe 50 years into the future we will have AI capable of meeting his needs and it would be really cool if time travel existed and we could just teleport him forward in time to a time where he can be happy (and be rid of him ourselves), but sadly that is too much to hope for.
For now we are stuck with games that have AIs that are far below human level and games where you can't just pick research randomly and hope to win.