Hunchbacks, Centurions and Cats are not brawlers. They are strikers. They hit and run cause they will break in no-time if they stand in a serious close range fight.
Having said that, Atlas with a medium/close range loadout makes the best brawler. No XL engines (they tend to reduce survivability) and the loadout must be quite heat efficient cause you want to deal constant damage without overheating. Awesomes and Cataphracts make descent brawlers too, although Cataphracts tend to break a bit faster if you are not careful enough.
My favourite brawling build during these days is my AS7-D-DC with 2 LLs, 3 SSRMs and an AC/20. 22-23 heatsinks (if you decide to strip some armor from the legs) ensure that you can deal constant damage by alternating between AC/20 and the 2 LLs without overheating very often, although you need to be careful and not overdo it. The 3 SSRMs are very helpful to deal with those annoying cockroaches and bugs that tend to scratch your back, especially now that we don't have yet collisions in the game and the lag shield makes the bugs immune to ballistics and SRMs.
Usual tactics with this mech is to advance by firing your Large Lasers, deliver a few SSRM salvos once within range and finish your opponent with a large bang from your AC/20 in close range where you can ensure it won't miss. AC/20 tends to be quite inaccurate against moving opponents and medium range so better save your precious ammo when you are certain it will hit. Or at least until they fix the bug with the ballistics.
PS: Now I realise btw why sometimes Hunchbacks and Centurions die so easily on my hands. They think they are brawlers



















