Pandora isn’t a separate mode, but a gameplay mechanic. That you didn’t realize this shows that Pandora Mode is fine where it is and I hope it stays near useless.
Though maybe you meant to say Heroes & Heralds from UMvC3.
Then we get into the real question of how good Gems will be for the health of the game. Heroes & Heralds is going in as a separate mode with the notion of very little, if no balance. This allows them to go crazy with the effects, but also means that some card combinations. will crop up as ridiculous unless steps are taken to limit them.
However, as Ono pushes it and you admit, Gems are being made with a competitive environment in mind. They very well may add a pleasurable layer of strategy and depth to the game. They will be balanced with competitive gaming in mind.
The real problems people seem to be having with Gems are acquisition methods and plain not liking them in concept as a preference. The latter is all well and fine an opinion to hold, nothing wrong with it; some will like it, some won’t, as goes most anything else in gaming. The former problem is much more worrisome. Could be time consuming. Gaming gods forbid they go “pay to win” with the stat changing gems. Or maybe we’re being worry-warts and only cosmetic gems will be priced, while any stat-affecting gems are either in-game or free DLC. Who knows. I’m optimistic on the concept of Gems, but stil lin wait and see mode on how they’re executed.
Either way though, I do not look forward to watching people pick their bling in tourneys.