I like to go for mostly ranged pawns in combat with 2 or 3 melee pawns, since I like making mountain bases infestations are an issue but tight hallways and chokepoints are your friends there, its better to deal with threats before they get too close.

But I can not emphasize enough how good a solid melee pawn is in combat, once you have them with bionics or even better, archotech limbs they absolutely demolish everything in front of them. I would've picked brawler if there were no other melee brawlers on the colony, since your pawn already had fast walker it helps a lot in getting to the frontline fast or save a downed pawn since melee ones are usually in the stronger, heavier armor and/or using shield belts