I said the same thing to some people last night, and farmed dem shards as fast as possible.
Realistically, I don't see how they can fix this without pissing off a large portion of the community. If they simply make the map the equivelent level of the highest person in the group, they make powerlevel or helping friends pretty hard.
If they put some kind of stupid restriction on blood shards, they punish lower level players from doing rifts.
I think they might just tweak Kadala to drop lower legendary items (punishing anyone not "exploiting").
I suppose, they could only allow your character to get any loot if you are in a map of, at least, your level. That might be the best logical fix, to not piss off anyone except those running these rifts.
They hate split farming as well (and have since closed beta), but haven't moved against it yet either. This could stay in game. Granted, I haven't seen any notes, so they might have a more creative fix in place.