Basically the only problems with the DH are the splash damage, there is none effectively which means you require direct hits, and minicrits. Minicrits in midairs are fine for airshots but for people jumping up and down and falling off objects it's stupid. It's ironic giving a weapon which is insanely easy to airshot with an advantage for airshots, that it effectively oneshots people midair. On granary mid in a 6v6 match I just instant gibbed a jumping soldier with my first rocket, it's not actually that hard to do.
Competetive wise, the weapon is meh. I personally use it but that's because i've recently got abit bored so its just quite fun. You lose an awful lot of splash damage but you gain the ability to do obscene single target damage, one shotting medics etc, if you can actually hit with directs, which with peoples ability to dodge isn't actually as easy as you think.
Remove the minicrits, sadface, maybe buff the splash damage to try to equal that nerf out. Or make the minicrits only work when the targets been in the air for a certain amount of time, it's just stupid instantly killing the medic on middle of a map just because he fell of bridge or train etc.