Terrible? No. 

From someone who hasn't played it, it seems the legitimacy of its criticism has little to do with its cost; what you're getting is fair for the price. Where it becomes questionable is if what you're going to get is what you want. 

As with most MMOs and games with extensive development times (MMOs being at the top of that list), it suffers from lag. Not the lag you and I are used to: the desires that ESO intended to fulfill have already come and gone in its development span. The modern gaming market has been experiencing a disillusionment towards the MMO model, a model ESO still very much uses. Hotkey combat, quests, PvP, PvE, endgame, repeat endgame ad infinitum. For those that have been through all of this since vanilla WoW, this is particularly boring. Many of the MMOs that have been released in the last several years have made honest attempts to innovate with this model, and they have all still "failed." ESO hopes to be different, but besides being Elder Scrolls, one may see little reason why it would be. 

If you've been through the MMO hullabaloo time and time again, from entry to endgame a million times, ESO will not be any different, and that's one of the primary problems critics have: it provides something that has already been provided for a million times, and they want something else. If you're really into Elder Scrolls and won't mind doing the MMO thing (or have never experienced it before), you could give it a go. It does provide a universe that many people long to immerse themselves in, and that becomes a significant selling (and surviving) point for the MMO. Bethesda are also reputed for their ability to make their worlds this way (though, personally, I don't care for it). There are other games that arguably do the MMO thing better and unarguably cost significantly less, but they won't be Elder Scrolls; if you're really dying for that dose of Elder Scrolls, it'll do the job.

So, no, it's not bad. The uneducated masses of gamers will shout money grubbing, but that's an expensive game to make and maintain. The problem is that it's in the wrong time period for many people; we've moved past the very passive hotkey combat system technologically, and that and many other parts of the MMO formula are getting rusty and fed up with. I'm sure they offer a free trial period for you to give it a spin, so if you're curious, go for it.