it isn't meaningless to say that HAM is better than tough. yes, HAM is not for everyone (in particular, it is not for people who don't have heavy armour). so what. shield master isn't for monks, polearm master isn't good for people that can't use polearms or quarterstaves, and great weapon master is not good for rogues. that doesn't mean those feats are bad, it just means that they're good for people that can use them.

HAM is good for people that can use it if they're at all likely to be on the front lines. it will most likely pay for itself over the course of most adventuring days several times over. no, it doesn't reduce the damage from a fireball or a dragon's breath attack, but it absolutely does help you survive those things (if you can use it) by allowing you to have taken less damage earlier in the day, and thus having more hit points remaining (unless of course every adventuring day for you at level 15 consists of waking up, fighting a single solo CR 18-20 monster, and then going to bed, in which case i suspect the feat being less valuable is probably far down on the list of problems your playstyle is causing). of course it isn't good for people that can't use it... no feat is.

the feat does not really need a boost. it is a good feat for people that can use it. it doesn't need to be any better than that.