If unarmed muties are sooo good, why dont we see them anywhere.
Simple, really.
As far as I know, they seem to be a joke in RT PvP due to their speed disadvantage. In the aspects they excell at a lot of approaches are valid. I reckon no one here exactly needs a strategy guide to farm geckos, raiders, etc, but that doesn't change the fact that, unless you play a HtH build yourself, melee mutants are in all likelyhood the most economic way to go about it. Also I've talked to a few people who got their info from the wiki and didn't even know that melee mutants are an affordable option, thinking they'd cost them 3k instead of 50 caps.
Also I am not exactly sure yet how well they mix with other NPCs. Ideally you want your enemy to target the 500 HP tank with good resistances, but I
think the enemy tends to target the first opponent to land a hit on him, which due to their speed are rarely the mutants. Therefore ideally you want only melee mutants to play to their strengths, but that locks you into 210 or 280 pp, if you don't want to waste any, however, most likely pp ammounts (unless going all out on a specialist) would be 230 and 240 (since that's where the perks are sitting).
As mentioned, they are that good, but in practical applications other considerations can take priority. Generally followers are a good bit more nuanced than "he has high HP, so he's good" and melee mutants might not be the best choice for every player in every situation, far from it actually. Considering their areas of expertise and their upkeep, they're outstanding, though.
My best Companion have 328 HP, he can shoot almost 2 times in a row with m60
I'd be interested how that works out for you. I tried burst weapons on comps before, but they still fired from their preferred engagement range instead of running in to hex. I'd have assumed the most valid choice for a good BG comp to be launchers, so I am slightly surprised.