I'm not a big MMO kinda of guy, truthfully the only other MMO i have ever played was WOW and it killed MMOs for me i hated it. With that being said i have looked into a lot of MMOs to try to get into because i like the idea of it. Now I think ESO offers its own unique experience as far as pvp goes, When i was in Beta and went to PVP zone it was awesome seeing hundreds of peoples attacking each other. Again though, i haven't played many MMO and maybe some other MMOS offer huge battles like that, but for my dollar ESO is the perfect MMO.
Loot: If by "100% Loot areas" you mean where you can go to a table and "steal" or pick up a fork, or apple or anything else you want. They simply can't do that in a MMO, i loved that aspect in the other TES games, but for a MMO I don't think any Server would be able to keep up with that amount of static objects.
As far as the arena comment, i love it. I as well am thinking about how awesome it would be to bet on other players in a PVP arena. That would be Awesome!
Edit for dungeons:
Yes in the last beta i went too 3 or 4 different dungeons with random groups and my brothers. They're out there you just have to find them first, under the group option ingame if you go to the "search" icon and select dungeons it will give you a list of dungeons you can currently join, click on one and hit "find group" at least thats what i found, other than that you have to search for one. After finding it have you buddies travel too you and go in the instance!
I went into Instances ( only people in my group where in there) and Public Dungeons. they where both ingame last beta.