I'd like to know what their point is? A divine leader class? Shouldn't they be a cleric build? WotC apparently doesn't know or we would have gotten a class acts worth reading. I always associated runes with arcane magic.
They are no more a cleric than a sorcerer is a warlock. The classes, while sharing similiar roles and power sources, are in completely different directions.
In fact, the comparison is apt; sorcerers are different than most strikers in that instead of doing massive damage to a pinpoint, they're better off doing massive damage to multiple targets. Runepriests are far more focused on melee than even the most strength based cleric.
The cleric's big advantage is healing power. They have nice buffs, but their buffs are by their nature situational. Their real strength is in the ability of every cleric to heal above and beyond baseline for most leader classes.
Where the runepriest shines is versatility. For a cleric, having something for offense and something for defense requires taking two different powers. This requires the cleric to make difficult decisions: does he focus on offense, focus on defense, or does he go half-way and hope for the best.
The runepriest suffers no need to make that decision. Every power has an offensive and defensive mode that allows him to change his strategy on the fly, without changing the powers he brings to the table. For players who prefer versatility, every runepriest might as well have the class feature 'Has 2 extra at-will powers' and the Spellbook feature of the wizard that lets you swap on the fly. This is extremely powerful. Their Word power shows it all... it's 1d6 less healing (and lacks healing word), but it has the capacity to buff your entire group with more damage or more defense. Other words will only buff their targets, if anyone is buffed at all.
On top of this, the runepriest is also encouraged to get up close and personal, and is rewarded for it. He wants people attacking him because that way he can hit them back... and hard. And, he always has an AoE around him buffing his team, so the front line is a doubleplusgood for him.
The cleric, on the other hand, is not as positional. He only cares if he can get in range for his powers. He doesn't actually desire a lot of combat attention. He's not built for it, but a runepriest is.