as there hasnt been any champion sneak peak or similar, and Dominion should be ready anyway.

I say wer gettin it tuesday

Riot just came back from PAX, and their champion design team is already is the works of another champion. Each seperate team performs different tasks, so the Dominion availability depends on the art/audio/game design team, while champions depend on the champion design team.

Most likely it really depends on which team can produce the finalized product first. Counting hidden timelines that the company keeps, most likely Dominion will be released very shortly after a few checkups on the servers, while the new champion will be on schedule regardless of Dominion's final patch bits.

You should drastically lower your expectations and just pray that the servers will actually function correctly.