What parts of 4e D&D do you find complex or deep, and what parts of 4e do you find to be good for new players and DMs? Or do you agree with ByronD, that 4e D&D is a child's game (newbie teeball)?
Given that BryonD's comment is absolutely absurd and deserves scorn: no, it's not a child's game. It's not teeball, whatever that is.
4E is an odd beast that you have to evaluate in two parts: what it means for players, and what it means for DMs. (In truth, you should do this for every RPG, because the game the players are playing is not the game the DM is playing).
For DMs:
D&D 4E is a game that tries to get out of the way of the DM as much as possible whilst still maintaining a mechanical framework for challenges that is (mostly) balanced.
For new DMs, the game maintains the ease of creating balanced encounters that 3e pioneered (for D&D), but takes the massive load of references out of the equation that 3e suffered from.
For Players:
D&D 4E is a game that gives a lot more "hard-coded" options for the players to use.
This is part of the disconnect with 4e for me: it's getting out of the way of the DM to allow the DM to do his job easier, but the power system codifies the options for players a lot more than previous editions did (well, in respect to fighter-types, that is).
A 4E fighter is far more challenging to play than a 3e Fighter at 1st level, IMO (if not least because you have to first grok the Fighter's marking power and how it works). The 4E Ranger is a better beginning class. You need to worry about teamwork more. Groups that master the teamwork of 4e - which isn't really that hard - will do very well indeed.
Cheers!