Let me compare to DotA2 which I play a lot. It's exclusively multiplayer and thus needs an internet connection, yet it's free to play. How much have I spent on it? At this point at least $75+ dollars. THIS IS THE FUTURE OF GAMING.
Valve has the right model. I know valve didn't create the F2P model but it has implemented it the best as far as I know. They have pulled more money out of me giving me a free game then they would have made if they sold me 60+ copy.
EA should of just given out free copies of SimCity. Given out free copies with enough features to keep me entertained without the need to spend money. Then releasing toolsets for modders to create items; resell them to us for profit.
The DLC will surely be created but based on how EA conducts DLC in The Sims 3, I expect expensive expansions and stuffer packs.