I still think there's too much emphasis on the layout/floor plan. Doesn't have to be EXACTLY like Seatguru. It's already been said -- the aircraft layouts are common among ALL carriers. A building, even in the same chain, is RARELY common (unless you're talking HI/HGI -- which, IMO, provides no value in a layout).
Some of you are overcomplicating a simple concept

Throw out the floor plan/layout (for now, if it's well designed, it could be added in ad hoc or at a later time). Like I said, just make it a Wiki, and post-as-you go. It's really no different than the Reviews here on FT except it's better organized, and you could standardize the information captured in a review.
I'm not sure what sdsearch means by incentives and rewards for this. It's open information that everyone shares freely, there should just be a better way to organize it. A lot of travel sites offer "reviews" but they're simple reviews, and 75% are done by vacationers who think a Holiday Inn Select is mid-tier

who knows this stuff better than FT :-:
I think it'd be cool to try. I do web project management and don't think this would be as difficult as some would think, and there's a lot more this could do (google map with nearby rated restaurants/entertainment, I experimented with the Wiki here on FT but it's VERY crude. The more I think about it, it'd almost have to be a blog-like app (so you could tag it by hotel chain, location, tier, etc), with a built-in ratings system.
=================================================
Hotels:
U.S.:
Hilton:
Hawaii:
Honolulu
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Hilton Hawaiian Village -- Rainbow Tower
xx001 ^ ^ ^ ^ ^
xx002 ^ ^
xx003 ^ ^ ^ ^
xx004 ^ ^ ^
xx005 ^ ^
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Something like that. Each link then opens up a summary rating -- view, room size, decor, comfy bed, HSI, status recognition, etc -- and reviews.
KISS methodology, works every time.