May I ask why you don't like the Headmasters concept? Is it the current overdose of non-HM characters being made into HMs, or a dislike for the concept as a whole?
I love the Headmaster concept, although canon wise I prefer the story of the heads being weak Transformers that make mech suits (Transtectors) for themselves over the human/nebulan combining shenanigans. To me, it makes a lot of sense and adds to the play value of toys a lot.
It's cool to have vehicles and little guys to drive them. Having the littles guys around mean you can have a city for them run around on without it having to be ridiculously large.
I will admit that I really love all the ~masters. Target? Yes please!! Power? They don't quite makes sense... but hey, I still love them!
I do think there's a bit of overkill going on at the moment, buteven with charcters that I wouldn't normally bother with (eg, Croc), I find myself thinking
"Maybe his head robot would be cool for swapping" <insert giggling emoticon here>