I loved this game ... to this day I feel like a baby born from this and FF14 would be the prefect MMO for me.
But artstyle wise ... they picked a style that I don't think ages well (something that would be improved by a FF14 baby)
Combat wise ... I like that it tossed the hard set holy trinity but they didn't think of a good alternative when playing with a GROUP. PVE doesn't feel like group play or team work, it feels like a single player game where other people just happen to be popping in. Part of why I LOVED Tera was because it got the combat right. Yeah, there's a "soft trinity" in that there are healers and tanks and melee/ ranged/ mid ranged DPS ... but it's an action game where no matter what role you're playing you're dodging and running and doing all manner of cool shit. Only reason I stopped playing Tera was cause none of the 2-3 people I know who play MMOs would EVER play it...
I love may of their QoL features, I love how you can walk around as a character is doing a monologue and hear their voice grow softer as you explore the instanced area. The glam system! I LOVE THAT! You only have to buy a dye once and you can use it forever and outfits you gain are forever in your glam locker (I think WildStar was also like this). You can dye any part of you gear unlike in FF14 where you gotta deal with complete non-sense dye behaviors.
I like the gear system! It's more horizontal progression, you can have different gears for different play styles for different weapons and skills with in your class ... lovely!
PVP is actually fun and not a joke like it is in FF14.
All that being said the reason I stopped playing is ... mostly cause I started playing FF14 and my lil group of friends moved me to that. The presentation of the game is lacking compared to FF14, the combat, even it it's a more engaging system, doesn't LOOK as good animation and effects wise. Group combat, as I said, is basically single player with other people. Mobs can't be "tanked", they will run after random people so everyone just zergs. Glams are way worse, can't change your hair without a cash shop item(I know, you can convert in game gold into Cash shop points ... but it's super easy to just change your hair in FF14), cut-scenes are not nearly as cinematic and the art style of the gear doesn't seem as cohesive.
Overall I really do hope they make a GW3 some day that addresses these problems but IDK if that's ever gonna happen.