Some personal observations that may be worth considering:
Castle Siege (hazards off)
It feels way too easy to camp on the left side of the castle exterior portion (I assume it stays in that mode with hazards off). Characters with excellent reach (swordsmen, tall characters), and angled projectiles (Yoshi, Belmonts) would be very difficult to approach because of the height difference and the platform above. If camping is a genuine concern, I really feel this one should be banned.
Pictochat 2 (hazards off)
Shorter then Final D (I believe), cannot be passed under, and may have a different distance from the blast zones, particularly the bottom one. If that is the case, it may be a viable alternative to FD for players that want a flat stage with less breathing room (little mac comes to mind). If match level banning is too complicated, make it share a ban with FD if it turns out to be different enough to be usable.
Wily's Castle (hazards off)
Not sure how it compares length wise to FD, but it does have tech/stick/wall jump walls. That alone can make it appealing for certain characters/match ups. Like with Pictochat, if match level banning a stage is an issue, it can be lumped in with FD but be an alternative choice to it for loser's pick.
Prism Tower
A moving stage, so obviously on the ban list. Should moving stages be permitted, this would be the one to allow. The transformations are very simple and each one could be a tournament legal stage to itself except for the sharking. Compared to all the other travelling stages, this is the only one that doesn't get a wall, walk-off, or extremely camp friendly platform during its route.
Pokemon Stadium 1 & 2 (hazards off)
Aren't the platforms in slightly different places between the neutral on these? Which is still a different from Unova and Kalos league's 2 platform layouts. I bring this up because 1 is technically different then 2 with hazards off.
Kalos Pokemon League (hazards off)
The concern is that the platforms extend past the ledges. Smashville and Town and City do the same thing, just not permanently. I would argue that Town and City is more of a hazard because the platforms can carry you to the blast zone on rare occasions, where Kalos cannot. I would at least let this one be a counter pick. It allows for extra recovery options similar to the smashville platform.
General thought about Hazards:
Because of the way rules are handled (Rules -> Stage -> Character), for sake of ease of setup most tournaments will probably default to hazards being off. it's clunky to constantly edit the rules to toggle hazards and you probably don't want players messing with the rules in general to avoid 'rule tampering' drama.
