This. I've got a runepriest in my game and he's all out of bubblegum.
As the player of the Runepriest in Tyrlaan's game, that was a gratifying blurb to come across.
We're heroic, and using inherent bonuses so take what I say through that filter. We're a two-defender, two-striker, and runepriest group. (Though one of the defenders is nearing striker-level damage.)
I'm really enjoying the runepriest. I wish there were more options for it. I find that my lower-than-average healing is made up for the fact that I can help end the combats quicker.
The flexibility of runepriests having two options is true but incomplete. First, which runestate when I end my turn makes a huge difference, often limiting my options on which power to use. I've found that with my group I 90% of the time want to give offensive buffs instead of defensive. On the other hand, my healing is (a) a great buff and (b) a minor action way to change runestate, so I'll trot it out differently than when I've played other leaders (bard, warlord & cleric).
The rune feats stink on ice - really, since you need so many before they are useful the opportunity costs get to you. Runepriests need to hit to add in a lot of buffs, and as a defiant word the only +3 proficiency weapon I had was dagger. Poof, there's a feat. I need to be in melee, and have the least HP in the group. There's a feat for that. (Wrathful have con secondary and that helps that.) I want to be missed to trigger defiant word, more feats.
But don't get me wrong - the runepriest hands out serious buffs (and some debuffs), and usually to multiple allies. I did up cards for powers on specifics to hand to players, and have standing cards for my runestates and powers that stick around that aren't linked to a character (zones, etc.).
Runepriests have their own play niche. Heavy buff, usually to multiple allies. Some debuff. Some healing. Not big on "chessmaster" tactical moves. Constant aura to help buff. Flexibility in each at-will & encounter power, with the limitation of being aware of what runestate to end in.
Various bonuses are fiddly and need to have a way that works with your group. Desperately needs power and feat support. I haven't played a strength cleric, but nature of the powers and general feel is different than the cleric I have played. If essentials was out a year earlier could this have been a cleric build? Possibly, but it's really got enough of it's own flavor that it would be hard to fit in. Definitely plays very different than the warlord, which is the only other melee leader I've run.
I always feel like the runepriest pulls his weight, and makes a difference in every combat. Part of that is having a group that makes good use of the buffs he gives out, but that's true for any leader.