Gate For the Good

Tweak the 9th level Gate spell to work like the lower level planar summoning spells, and have the gate call forth a creature based on the caster's alignment.  Evil PCs still get the balor from the dark realms, but have the good PCs get gate to the celestial's home plane that calls out a celestial being of equal standing to the balor. And the neutrals a.... well, not sure there's a "middle ground" plane for them, they could probably do with still getting a balor.