Make the above Clever Shot usable as an RBA, and you've got a pretty strong Bloodbond Seeker.
Spiritbond Seekers really badly need a free proficiency in some decent weapon. They don't even get handaxes out of the box. They might need help beyond that, but I've never played one.
I think Battleminds are mostly OK, aside from the aforementioned MBA sucktitude. Giving them a basic Con-based OA would be a pretty minor thing and would already improve things quite a bit; I'm not sure if they really need a full MBA.
Runepriests mostly need nice class feats that aren't rune feats. Some more power selection wouldn't hurt, either, but the class is unfortunately difficult to extend because of the way runestates work. Every new power needs to support destruction/protection, and it's hard to add a new state without rewriting the class. For example, even the paragon path states in PH3 mostly suck because class powers don't support them. Rune states were a neat idea but the implementation makes expanding the class a huge pain.