I too am disappointed by the lack of a Hot Seat mode. I have heard, as well, that they intend to patch it into the game, but that has only come from other people rambling on the forums. Personally, I believe they removed or did not add Hot Seat in order to fuel additional sales of the game.
In respect to the game I have to say that I'm quite upset about what they've given us. Personally I don't like the fact that when you're building a nation your culture does not merge with all of your cities to create your state. You have to buy tiles in order to spread your culture and you simply run into a situation where you don't have the money to link your culture to all of your cities...so your civilization looks haphazard. It really looks like a simple collection of city-states across the landscapes. Also, the diplomacy was not as in-depth and I was hoping this fifth incarnation of Civ would be. We're at Civ 5 not Civ 1....this means the game should evolve and get better not languish in dead game styles. This game actually reminds me a lot of Call To Power.
Now that I've said that....what I like about the game is the hex based tiles, multi unit graphics, and the ranged combat capabilities. Overall I think that I give Civ 5 a 6.5 on my love it meter. The fact that the Diplomacy seems rather like it was rushed and the features are not well explained really disappoints me. A Sid Meier should know better!