try bringing along regenerators and using them between respawns. also, there are healing plants around the arena that act like hypos. If nothing else works, lower the difficulty. I've gone through that mission multiple times just fine, it's one of the best ones in the game. Also, don't just button mash when you get close to them, there are attack combos that give your melee weapon attacks more damage (there's a page on STO wiki that details those for you.)
I'm going to have to go with Aces_High on this one. "Colisieum" is one of the more interesting missions as part of the Reman FE series. You should look for the herbs in the arena that are doing the same "glow" that other interactable objects do, and keep running. I've never been killed in this mission,
The melee combat isn't implemented well enough for you to be able to rely on it.
i sense a challenge..
I think i'll make a new character next week, and proceed to run it up to admiral using only melee combat. as well as on my Boffs..
the problem isnt with the game, its with your inability to use the mechanics everyone else is using. as a pointer, one of the most basic melee combo attacks can be created by pressing 1, 1, 2 with almost every melee weapon, including bare-handed. Frsutration is one thing, complaining about a mission that most people can complete with no problems is a little beyond that.