Well its going to be a somewhat long post so enjoy the reading. I have been playing the western version of this game since it was in beta during 2015 and I somewhat followed what has been going on since then, so in order to make my argument more solid and understandable it is necessary first point how class progression has been in this game.
Will start with beta period and level 45, obviously, during this period Summoner was crowding the arena ranks for several seaons, most of the 1st to 10th rank in Arena was Summoners, the strenght of the Summoner was not only a lot of iframes and escape mechanisms, but also his cat partner, which can tank pve objectives aswell and the sunflower AOE damage being insane, so having some Summoner in your friendlist was crucial, you could do anything, dungeons, faction pvp, tag matches, anything was possible, and mostly easy to play with.
So we played the beta game, a lot of Summoner ... then game was announced to be released for the 16th January 2016 and along that they announced devs planned to give Assasins a blue buff because (this is the devs statement, not mine, have it mind) "no one would play with Assassin in party as they're a solo class and can't offer anything to the group".
This move made the game look like this in DPS tier damage : Summoner, Assasin, FM, KFM.
Basically the buff classes plus the Assassin that been always best (or almost) sustained dps class in the game plus FM which was during level 45 comparable to what today is Gunner, a burst class.
So a bit later they released Warlock, and with that people started to get more and more picky to do content with other players, it was basically mandatory to have a warlock in your party or no decent player would join you, the best composition was having 2 warlocks (one for SB and one for TD), a BM to tank a KFM to blue buff an SIN to dps and a FM to burst. With that combination you had all buffs plus hongmoon block and ICE, so no reason to play with other classes than those.
At this point and after some nerfs to the bullied classes, SF was released, a shift in the B&S meta that took place a while ago made Summoner irrelevant at this point since they weren't using cat taunt anymore and the new clase was eclipsing by far summoner as the SF can tank without a cat, can resurrect whole party with a press of a button and instantly, plus it was the new thing in the game so everybody was excited about it and just killed the Summoner basically.
Time passed and Gunner was released, so the slot in the party for the FM was replaced by the Gunner, higher burst and alphacall so basically you can burst down the enemy in 30 seconds, what equals to Soulburn twice.
Then the warden came into play and eclipsed warlocks, they were basically relegated to use TD, and today is even worse because Shadow warlocks don't want to TD so honestly if I have to chose I go warden definitelly over a warlock because they can tank, they insta soulburn and they're harder to kill and have less mobility restrictions, so all in all warden is better
And now we reach the point where Archer is released and comes to eclipse Gunner, in the actual meta bosses are shielded to prevent bursting them down and archer has somewhat decent burst and a huge sustain making it at the moment one of the top dps classes in the game if not the best.
So there's 2 classes I haven't talked yet in the post and I'm sure almost nobody did miss them, those are the Blade Dancers and the Destroyers, while old classes get eclipsed by the new ones, BD and DES been eclipsed since level 45, they were classes only good at PVP, for the rest they're not really wanted, you get hmblock from a blade master and on the current state of the game with 3rd spec out blame masters do have better sustain and better burst plus they are natively tanks while blade dancer isn't, on the other hand Destroyer is eclipsed by FM because higher burst damage and good sustain, plus more mobility and a ranged class is always less problematic to play than melee, So why would you play with BD and DES?
The answer is the Grab, BD and DES were designed to be supportive dps class, and with the grab they can enhance whole party damage, problem is the developers failed to make it shine because while you grab you lose your own dps and also your team mates lose the targeting, which is not much of a problem on ranged classes but for melee it is really hard to find the hitbox, its not a new issue, its there since level 45 and they partially fixed it and got better but its far from being perfect.
So what do I propose is a Grab rework, keep it like it is for the PvP as it is a core part of the class mechanics, however in PvE make every boss and mob to have a different reaction to grab, my proposal is that acts like marking system, wherever the mob/boss is under crowd control give us the ability to debuff the boss with our grab but without grabbing it at all and making the whole party gain a damage buff that is equivalent to BW or BB so this way you kill 2 birds with a single stone, players finally will want to colaborate with CC because they get dps increase by doing so and at the same time you're giving BD and DES something that other players want to have from them, making them a popular choice to play with, instead of the most discarded classes for any raid or dungeon content.