If we're seriously talking about adding stages to the list (although that should probably be its own topic), Umbra Clock Tower is the most obvious candidate IMO. It's got Battlefield's high ceilings, but with platforms that come and go like Town & City, so you can't just ladder up to the top all the time.
(The music is all kinds of awesome, too.)
Criticisms (that I can anticipate):
- Temporary walkoff form
- Solid platform form
- That one form with a platform underneath the stage
- QAC glitch on clock face
- Fortitudo
Rebuttals:
- Temporary walkoffs are nowhere near as big an issue as permanent ones. We put up with Delfino Plaza and Castle Siege for ages, and their walkoffs are much more prevalent (Delfino) and long lasting (Castle). Umbra's are rare and short lived by comparison.
- The solid platform is a) temporary, b) moves right to left so it c) can't be circle camped effectively and d) does not appear frequently enough to be a major issue.
- The platform under the stage comes with grabbable ledges, which makes it easier to pursue a player trying to take advantage. Like all other platforms in the stage, it's also temporary.
- QAC glitch was patched out to the best of my knowledge.
- Fortitudo does exactly nothing to the battle and isn't even always visible due to how the stage enters and exits Purgatorio basically at random. At most, it's a mild distraction, but speaking from personal experience I barely notice it anymore. (Playing Bayonetta 1 and beating the crap out of it helps too.)
If Smash 4 mods ever take off in popularity I have a whole list full of ideas to modify existing stages to make them more palatable, but I don't want to completely derail the thread so I'll just stick with what's actually playable.