Referencing a couple of parses would help your assertion appear to be more than anecdotal.
Quick math based on a few personal ICC logs:
Corruption/UA amount to roughly 50% of my damage. Slightly less if I lose the initial power-corruption for whatever reason, more if there are adds that warrant dotting up. Assuming the set bonus is responsible for 10% of that damage, I conclude it's a ~5% damage increase overall. Feel free to point out mistakes in that logic.