Man what game are you playing, and what do you mean by planning ahead?
Sure you can build specialist cities, it falls into 2 categories
1. Production
2. Commerce
I will neglect the mention of specialist cities as well, you just dont ever seem to need them. The case here would be a city thats all farms, but I found the benefits of such a city in Civ 5 useless due to the way great people add improvements to tiles. Although I guess you could actually have a "science" city whose only job would be to grow massive.
1. Production cities spam buildings and units, obviously the mine and sawmill are the choice here.
2. Commerce cities... trade post.
That about covers the stupendous 3/3 improvements we have at our disposal. Farm is a given, and all city types will require it to grow. Alot of the buildings such as watermill, and windmill's which used to be an improvement are now not enough worth their cost. Also the only improvement that gets benefits from science is the bloody farm, neato gang!
Now lets look at Civ 4.
Here specialist cities actually mattered because science wasn't based on freaking population, you also had a huge amount of tile improvements you could select from and I'm not going to do an exhaustive list for the purpose of this argument.
Now by plan ahead I am assuming you mean, dont build buildings you dont need, and select your civics wisely. Well I would argue that's not really innovative, its actually rather restrictive. I HATE the fact that the new civics are 100 percent inflexible. I find it boring that I can be ETERNALLY at war and my population has furs so its cool with that, hell I dont EVEN HAVE A GOVERNMENT I can alter. Religion is hit or miss, but something was very entertaining about the viral way it spread.
Combat was about the only change I enjoyed about Civ 5, too bad its going to need a patch to fix (hopefully) if that happens It might become palatable again.
The last point I'll make is in regards to the culture generation and science vs the aquisition of cities. I made this point in another thread, but here it is again.
You are against Monty (this is my last game). You control 10 cities in North America, all upgraded tech wise and culture wise, with an average populus of say 10 -12 people. Monty has devoured all of Eurasia and sits on close to 40 or 50 cities, his population is probably lower, say: an average of 6-10 per city. You are paying an astounding amount for the higher tier science/culture improvements, while his sprawling empire only allows him to purchase the basest of upgrades.
So who wins?
Monty does EVERY GODDAMN TIME.
Why?
Science = population
No penalties for empire sprawl
Happiness and luxury aquisition = win, more territory = more luxuries.
Thats the basic scientific formula for Civ 5. Cities trump improvements. So while you might have 10 really really nice cities, his 40 mediocre cities will CRUSH you in every way. More income, more culture, more science, and unless you get on the warband your lost. A fix for this "might" be to get rid of the puppet city concept.
That about sums up my philisophical disagreement with Civ 5's changes, you'll notice its not careless ranting about change, its specific disagreement with change that has resulted in oversimplification, and mandated war as the only means to victory.
Phew.