Personally I feel the interp-split was never that heavy - as noted before, at least in CK's tourney voting, switch hype came up a fair amount - but sure, definitely just issue a ruling, one way or the other, since it's best to avoid such interp-splits. I do think the cast is underpriced for Switch hype but such divergences in price aren't uncommon. More to the point, I think Switch is cool and interesting, and letting it come play in the Dungeon is where you get to show it off far more than in a duel. Slugfests might be easier to interpret but they're not as fun; weird swingy matches are neat as long as the interp is clear, and if Switch is allowed it's usually very clean to interpret. (For example, my proposed team didn't have a single broken thing it could use Stocke's switch for, and could fall back on Stocke's own skillset quite a bit; sometimes it could get double-MT heals, sometimes it could get double-status healing, sometimes double-Elincia beats, sometimes Stocke can plain hit something or revive.) Additionally, the most powerful use of Switch / Trans-Turn is to artificially speed someone slow-but-broken up, and since Aht wasn't in, that wasn't a problem. Well. Except for Speed?, Body Charge, or Jane. As has come up with Pyro / Djinn.
I think this is just an overreaction to Djinn's team. Yes, Djinn's team is "broken," but that's kind of half the point of the Dungeon - either come up with a cool theme team, or figure out some haxy combination of characters, or both. Jane is far more the "problem" in Djinn's team, but there's so many horrible things that can be done with mass team initiative, I consider 3x VP2 Lenneth turns far from the worst potential. (As for why Jane teams crashed and burned before, I think that was due to thinking of her as a one-trick pony who just did Follow Me + some plain bad luck.)
As for claims that a specific ruling on a per-character basis is unclean or inelegant or whatever, that happens all the time. Look at FFX Rikku or FFX Yuna or whatever; these characters are insanely swingy if they don't have clarification on which "form" they're allowed, and it's not a big deal. In fact there's the entire "Dungeon Stuff" wiki page with the rough guidelines for characters, many of which are set-in-stone for sanity's sake. Explicitly setting rulings is a good thing, not a bad thing. So yeah. I personally would prefer to keep all the RH characters and cheerfully use them as enemies as well - just, well, don't use them on the MT floor of course. (I also would prefer that the RH characters prices be hiked and Switch kept, or even for characters to be split a la Nall, but keeping Stocke & Raynie with a no-Switch clause would be fine as well.)