I suspect that most people who criticize it for being too much of a single player game are drawn on the fact that there are actually class quests and stories involved and the added depth of the voice acting which is somewhat unheard of in recent MMO titles or at all to this extent. It really separates you from everyone else and can, at times, feel like a single player title within the above examples because it's your story rather than a story everyone has access to but that is by no means a bad thing. I like it but I also know those who are on the fence about it.
Most of the end game disappointments have been by those who just blindly jumped ship from World of Warcraft who happened to join WoW after the TBC era in that they expect a fully fleshed out end game with countless things to do. ToR is like many MMOs in their infancy and the end game is a little sparse compared to everything in between. The fact of the matter is is that if Bioware can keep up their bug stomps with little downtime and provide content updates on a regular basis to establish decent end game (be it pvp or pve), this will be around for a while.
I'm willing to be reasonable and wait for the content to come and the subtle bugs to be ironed out (except getting stuck on rocks in falling animation - ugh) and if that means all the WoW trolls will leave Fleet General and go back to Trade, so be it.