Some points to remember:
-All MMO's go through the initial growing pains that plague the genre. WoW was nigh inaccessible for weeks on end due to server side issues...I remember being gifted a free month and a half because of all the issues, so it's to be expected that there's going to be lag issues until players spread out across the game's universe. Look at what happens whenever a new expansion comes out, all the players clog the starting areas until the content gets into it's second or third week then the issues largely become self-regulating.
-In that same vein, keep in mind the beta weekend stress tests are just that...tests for the server and to give players some exposure to the game before release... they are NOT current clients either, they are often several months old and the "Elite" Beta testers have the most current clients which fix a lot of the bugs present in these beta versions.
-Everyone is going to make the comparisons to WoW. Why? Because WoW set the bar. EQ was king until WoW came along, and promptly handed over the crown, the keys to the kingdom and called it a night (though EQ is still going fairly strong). WoW Revamped the genre and became what every MMO since has aspired to become, and surpass. Lofty goals to be sure.
-Balance is an impossibility considering everyone wants the differences. Unless the classes are absolutely identical in every regard (thus removing any semblance of story and variation) balance is a pipe dream. Yes, something's need to be tweaked here and there, but that's what the development teams are for, and something even the vaunted WoW struggles to achieve constantly. Fixing one class might make another much more powerful because it was kept in check by that other class. Then comes the question, what determines being OP? SOmeone might be more adept at using their class abilities, or reacting to multiple targets and CCing like a boss, or maybe they're adept at using movement and terrain to their advantage. Warhammer comes close to havign balance, but that's because most classes mirror others...then it becomes an issue of RNG (Random Number Generator), Gear, Teamplay, Latency, and other mitgating factors.
Point is, this game offers the feeling of a much more visceral immersion in the gameworld than WoW offers. How many years did it take those guys to build the Inn in Westfall? You immeadiately get the sense of being embroiled in this massive conflict whether of your own volition, or merely being a soldier for hire. In my playing of a Smuggler, Bounty Hunter, Trooper and Sith Warrior, I found each story was its own flavor, each class had their reasons for being there...
I was somewhat timid in approaching the game because of Bioware's typical novel sized conversations between PC's and NPCs, but I was glad to see most conversational custscenes are kept fairly short and to the point, but have their own quirks. The NPCs FEEL fleshed out, and possessed of their own personalities and motivations.
Overall I was truly impressed with the product I played for the few weekends I had access, and can't wait to get my hands on the finished product. I'm certainly approaching the game with an open mind and understand that the growing pains will be there for a little while, but I think the end result will be a supremely enjoyable product. In that regard I really don't think anyone who judges the games "Awesomeness" or "Suck" factors in terms of best-ever or worst-ever are doing so half-cocked, as it's an unfinished product most were exposed too.
If you loved the game, GREAT! If you didn't like it, that's unfortuante, but where it wasn't JUST a sneakpeek, it was a beta - meaning your input is looked at much more than it might be three years after the fact. If there's something you don't like, mention it and offer improvements. When gamers don't bother to make suggestions or only provide criticisms with no constructive element, it seriously hinders the development of the game. Who knows, that little idea you suggested may be the thing that changes it for not just you, but everyone else and brings them into the fold, or makes the other players go: Wow, that's an awesome idea.