A few observations:
Hotels get reimbursed at a very respectable rate for award stays, so it's not unreasonable for a Platinum to expect an upgrade on an award, assuming the space is available.
Like DADISGARYK, we've had some very sweet suite upgrades, and some of those have been on award stays.
Hotels may also be more amenable to suite upgrades for short stays (which lessens the chance that someone will want to pay them for the suite while you're in it for the price of a regular room).
We have a friend (Marriott Gold) who often stays at the same hotel we do.
Our overall upgrade-at-least-to-Concierge rate: about 95%.
Our Gold friend's: about 50%. Generally he automatically gets Lounge access these days (something not always true in the past).
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