My biggest disappointment is that Reggie basically told the hardcore gaming audience "we don't care that you want online play, we think what we are doing now is just fine, thank you". In other words, a big screw you to the online gamers. Not that I care personally as I don't really care too much about online gaming, but I know many people are. At least they announced WiFi for "many" players on MK:W.
Otherwise no new games really announced we didn't already know about except for WiiFit. SMB:G has been known about since before launch, as has MP:C and SSBB. At least we know when they're coming. I just wanted to see something actually new and interesting, which I didn't really get.
If they come out with some decent use for the WiiFit pad for a snowboarding/skateboarding type game or something that would be cool, but no developer is going to use a peripheral like that I don't think, since not enough people are going to own it to make it worth the developers' time to create specifically for it. It's like the NES Pad, it just never got used. The Zapper is a bit of a joke as it's just a new plastic case for the remote and chuck and the Wheel is a total joke.
Those are my thoughts.
In their defense though, this conference is not designed like previous E3s with massive WOW!!! appeal for the masses, booth babes, etc. Being a more industry internal conference it'll be much more subdued, hence the complete lack of enthusiasm from the audience - although that was largely due to Reggie's absolutely horrible, non-engaging public speaking ability.