yeah any class can be a sword bearer, a hunter just makes it faster but frankly its just as easy to fuck things up as a hunter since there are a lot of points that can go wrong (melee stab, invis drop, invis pickup, etc). A warlock or titan can jump up from either side rock and go kill him just as easily, and there are three different ways to keep the boomers off his back:
1. any person can go on the walls behind the towers (towards the far end of the area) and just melee/shoot towards the boomers above them. this keeps the boomers attention on them the entire time, they can just stay there the whole fight and be safe. this is a great job for a 30/31.
2. a titan can drop a bubble every time on the side the runner is going up, where two skulls are on the ground (you'll see it). titan uses the +5 sec bubble perk and just stays inside the bubble, a pro one can side step a bit and gallahorn crota but not really needed if you have 4 other people with galla/HoC.
3. a sniper can just ping shoot the two boomers the entire time the sword bearer is active, he can even take one out before you run back in to make the run inside easier (or you can all stay outside and huddle on the opposite side ledge of crota).
that said none of the crota HM drops are worth doing the fight for, the handcannon sucks the crux weapon sucks fang is all right but imo abyss defiant is generally better.