" How is it a healthy play pattern when all tournaments and high ranked games are filled with Wraith, Pathfinder, Wattson and Gibraltar? "
They're different issues? Those legends are the meta more because of their own abilities, than the lack of ability on other legends. That is to say; in order to buff a legend like Caustic to a point where he competes with their inherent capabilities is likely to create a very broken Caustic. As much as we hear players constantly say "buff everyone to be as good as X, don't nerf X!" it's not sustainable. I think Gibralter is an example of that; when brought up to a level that competes with the top tier legends, which data wise he still struggles to do (even at his best) he becomes unfun to fight against.
" I wish they would dare to make as much changes to legends as they do to weapons. Weapon balance changes has been really good overall."
Thanks, I'm glad you're happier with the weapon balance situation. Weapons are far easier to make balance changes to because they're much more data driven than the legends. We can tweak damage, raise/holster times, viewkick, magazine size, etc... without much (if any) downstream work. Changes to things like fire rate and reload speed are bit more involved; fire rate requires audio work, and reload speed requires both audio and animation if the changes are drastic. New hopups tend to require audio and FX, as well as significant lead time for ping voice lines.
Legends, on the other hand, have far fewer knobs to tweak. Cooldowns and damage are easy, but a lot of the ability durations require audio, animation, and FX work to adjust. Abilities themselves can require significant code work, depending on the type of change.