The game is purely won/lost in the opening colonising rush. It is just that simple. So as liqo_CZ just mentioned, the starting position ultimately determines your game and that of your AI opponents.
Personally farms are inconsequential. Find one planet with a farm or two close together and build Kimberly's Refuge. Stack a few farmers as needed. Food is now sorted for your empire. The rest are mostly bulldozed for better planet bonus stacking unless convenient to assist city pop bonuses. Obviously there is a little more to it with techs but that is the basis. Very easy to max out 20 planets with minimal effort and tile wastage. My current game against 15 godlike AI I have 450 pop with about 5 farms spread over 25 planets so it is not only feasible but effective
If we had open pop limits then farms might be an issue, but due to the tiny pops nowdays limited to just the planet class, I fail to see how this is still an issue for people. I miss the old days of having a few thousand pop in my empires. The thing is with this new system is the AI seems better able to use it making it more competitive which makes it an overall win in my book. I am sure most people have come to grips with how it works and adapted. I wish people would stop complaining and just learn how to adapt.
Back to the opening post, think of farms as a use it or lose it scenario. They produce X amount of food for that turn, which spoils and is unavailable for the next. But if you have cities, that food is now used to support/grow pop for that turn before it spoils.
