SimCity - I GET what Maxis is doing.
After playing this game for 16 hours on one city, I GET what they are trying to do.
Instead of expanding outwards, your options are to work with what you have and rethink your city layout and make room for upgraded buildings and future expansion. By limiting the size of the map, planning/layout is a HUGE factor. This creates similar challenges from the older Sim City's but at an earlier stage. I also noticed that the zones grow instantly once the utilities have been set. It would be overwhelming to manage a gigantic city in addition to completing side missions from the SIMS.
In addition, the multiple cities allows you to take advantage by starting fresh and focus on other areas to help the cities share resources to work for the common goal. This adds a new experience how you can obtain resources instead of just constantly building additional buildings (expanding outwards). This also forces you to take advantage of the multiplayer to have others help create / manage the other cities which is alot easier and less time consuming.
Maxis could have kept this formula and allow more space to build, but I can imagine performance being an issue with their current engine. Maybe EA will release a DLC which you will have to PAY to remove city restrictions. None the less, I give them props for trying something different then sticking to the traditional style of gameplay.