Eh, neuro isn't really a damaging spell. It does do damage, but that's not why you cast it. :P

I wouldn't say transmuters are even competitive with invokers in the damage department -- transmuters do have some spells that you'll see throw big damage, but it's unstated that these usually follow the transmuter spending time getting corporeal softening, decalcify, or both in play, and that they've got fairly hefty lag.

When it comes to damaging multiple enemies, the invoker is clearly superior as well.