This isn't really an ICS nerf, just an ICS recalibration. 1 more tile between cities+25% higher settler cost probably works out to the map actually filling up faster. You will have fewer cities and be paying +1 gold per city to link them, and losing 1 gold from the base tile, however, we don't know how the math will work out with trade routes now.
Before, you could fit one city per every 7 tiles with perfect spacing, which in turn made "optimum pop" 6 as far as tile usage was concerned. Now as you'll see here, you get an average of 13 tiles per city; your 7 base tiles, +2 overlapping with each of the other 6 cities that are adjacent. Giving each city one of the two tiles that it shares with each other city, it works out to 13 tiles per city, or 12 pop.
http://s1181.photobucket.com/albums/x434/herojon/?action=view¤t=hexmap16x16.gif
Looking at the patch notes, you now get +3
for Coliseum, +4
for Theatre, and +5
for Stadium, working out to +12. Amazing, now optimum tile usage aligns perfectly with the maximum
from buildings, ignoring Circuses. That means with Theocracy alone, you can be at +3
per city -2 from the city itself for a net of +1
per city with no other SPs, no luxuries, nothing else. Or you can do one of the many other social policy methods to nullify unhappiness from cities. (Personally I want to try Oligarchy+Military caste. It's the most hammer intensive but it's also the only method that will give you a superior military and defense. A big deal in Deity games.)
Anyways, if before you were building a settler for every 7 tiles, and now you are building one for every 13 tiles, it doesn't take a genius to figure out that there's almost half as many possible cities in a game now. Certainly, the number of cities will decrease by more than 25%, which means that from a hammer standpoint, the 25% settler cost increase is more than offset.
All this shows that the real difference in ICS now, is that ICSers will be developing their cities more, but that they will have more time to do so as well. The question has become what the new trade route formula will look like. Patch notes stated that Ultra-small cities won't get the normal amount, and made it sound as though everyone else will now get the same amount +a bonus from capital size. No idea how significant that bonus is, but if capitals are going to be at least 12 pop, I'm sure it will be equitable.
I'm predicting the new ICS will involve adding at least one growth building, or investing in landed elite (+15% growth/+2 for per city according to patch notes), a stable or another production building, if plausible, and building all 3 happiness buildings. Since Stadiums come so late in the game, holding cities other than the capital at 7 pop for a while now seems likely. Maybe it will be city/library/coliseum/whatever/theatre/do stuff until you grow to 7/settlers until stadiums come available.