Summons should recieve creep upgrades.

And generally any 300+ mana spell (Assuming Fire Elemental/Infernal) is much better than the summon early in the game - so they have the advantage early. It becomes a late game/early game clash - though it would be bad in -anns as they would be good at all stages - and even so - a simple Purge/Dispel own them.

Lesser elementals (I think, haven't looked at numbers in a while) would also die easily to similar mana cost spells early on (In 62 games). And the amount scaled wouldn't be much at all compared to creeps.

I actually also disagree w/ the idea of then upgrading w/ creeps and would instead prefer to see them max out w/ enough power to be good in a 40's game. The gap from 40's to 60's should be made up with elemental items.