One of the things Lord Vader requires is absolute maximum relic levels on the team. A lot of people don't seem to understand that but the way his mastery increase works it takes a couple r8s at least to achieve full value. Whereas with Kenobi for example he's still going to ramp up damage no matter what
So that in mind I find most of the people who complain super hard about LV being trash are people who are running him with a couple r3s on the team and that genuinely does make him really mediocre
Now if you want to complain about that being a crappy thing then sure, I get it, but the character itself is totally fine if put in the right scenario (again that being LV with a bunch of r8-r9 teammates)