I do think it's a bit odd considering they are currently labeled as DPS, but I think it's just how things are going to play out in the future for FFXIV (or were originally intended). As the game continues to progress, Hybrid classes are to be added, at least according to Yoshi-P. I think the only Hybrid in the game so far is the ARC ---> BRD. That's why, I'm guessing, they left the LB as heal.

In my opinion though, would be nice if each LB tier did something different. As it is, it makes no sense. Sure, in rather extreme conditions, the LB is useful. But every WHM I've come across is awesome as is, so there's never a need for it.

My thoughts: if it's considered a DPS, let it DPS.

If, and when, it is officially a Hybrid, give it a Hybrid LB. Tier 1 is a minor DPS Buff? Tier 2 is a Heal - and Tier 3 can be anything from a full Revive or even greater DPS Buff or even Debuff. Spit ballin'.