This is Vegas. There's now no such thing as a really 'quiet' midweek, so be prepared to pay for the upgrade (no, not the $20/50/100 trick) or prebook the upgrade by calling them now.
No matter what you hear, Wynncore employees are trained NOT to accept bribes for room upgrades. I've seen front desk folks lose their jobs for playing that game and getting caught. Steve Wynn knows that bottom line, he needs to sell those rooms in this economy. Unless you're rated and have a host, just being given a suite is highly unlikely. The most you'll get for free would be a higher floor, but to me that's not an upgrade.
Call Wynncore and see what they offer you to bump up now.
BN