As someone who has negotiated aircrew contracts in various places, I'll be perfectly honest and say that both the hotel and the airline prefer that post-facto feedback and complaints be channeled through the contract reps on each side. In fact, I've actually had a few properties insist on that being written into the contract (that they will respond and channel all feedback correspondence via the airline rather than to individuals).

Of course, this does not excuse a deficiency of basic maintenance and housekeeping essentials (which should be raised for CORRECTION with the hotel immediately). However, once you check out my suggestion will always be to forward it to your manager to pass on to the folks negotiating the hotel contracts. These are much appreciated in the periodic feedback meetings between airline and hotel reps and are often used in negotiations for contract renewals, etc...

Finally, never ASK for loyalty benefits on a crew rate, no matter how small. These are often extended as a courtesy but very very rarely as an entitlement.