It's artsy/goth/romantic especially each room designed by a different artist... as long as you don't mind noise as it is a very party friendly hotel.. a locals fav.. my fav and it IS small they are very friendly with VERY fair/good prices on their awesome rooms. The staff is very laid back and Fri-Sun all say and night there's a Dj playing and it's voted locals #1 after hours.. check it out

Hotel Suggestions that are on the Strip..

Here are a few suggestions that don't have a keycard or security where you would need to come downstairs.
Planet Hollywood
Cosmopolitan
New York New York
MGM
Luxor
Flamingo Hilton
Westgate(used to be the hilton)
Harrah's
Paris
Bally's
Mandalay bay
Hooters
Monte carlo  
Westin hotel
Platinum hotel

These are just a few I thought of that fit your criteria.
Another response suggested the Artisan this hotel is not on the Strip.
If you are not looking for a hotel on the strip then Artisan might be another choice.
But that hotel is very dark gothic feel.
I would suggest there other property that is close to the Hard Rock hotel called Rumor this hotel does not have that dark vibe.
Whichever hotel you pick have fun!

1. PH - no security
2. Cosmo - did not see any until weekend (they had disabled the keycard in the elevator)
3. Monte Carlo
4. MGM - showed up late at night, after 10pm

 
I think as the summer months draw near, security might increase, due to increased traffic.  

you could look at Places like the Renaissance Hotel,

Mandalay Bay, Four Seasons, NY NY, Monte Carlo, MGM Grand, Bally's, Caesars Palace, Cosmopolitan (my favorite!), Bellagio to name a few!