Skate 3 was a cunty THPS 3 gloss fest, but the prob is Black Box was ripped apart after Skate 3, so 4 just ain't happening.
I would have loved a more Skate 1 vibe from 4, with nothing more than a better look, honed physics so they're less silly, less glitchy hardcore mode, more solid career story with photographer control and 'session' multiplayer where you can hang with your friends at a spot you set with a marker, watch each other skate as it rounds your turns. Basic but awesome upgrades.
So yeah, DLC would be fine for that, and seasonally upgraded boards, or be cool and let us put photos on our decks so we can upgrade our shit.
But yeah, not happening.