You are kidding, right?
Not easy to get sacred bonuses. These stack, don't forget. Also, built in light spell plus up to +21 HPs on your whole party for 1/round per level?
Seems just about right.
Eh, I agree it seems a bit underpowered for a 5th level spell. As a 4th level, it would work.
It seems underpowered...by at least 3 spell levels. Give it a party buff effect, or cast it as a swift action to fit in with the 'Burst' concept.
Considering Aid is a level 2 spell, a spell that's similar to Mass Aid (so to speak) probably doesn't belong there.
I think the general idea is that Mass XYZ should be 3 or 4 levels higher than XYZ, although using that logic you end up with some less-than-popular spells like Mass Fox's Cunning (which I'd never waste a level 6 spell slot on).
This is also comparable to Greater False life with an area of affect plus a combat modifier. GFL is 4th. This does more than GFL and is therefore a higher level spell.