Referring to the wild magic subclass, I believe the reason people thought it may not be implemented with sorcerer right away was due to some of the features using reactions. I believe there actually was another tweet, like rag said, talking about how they made tides of chaos work without using reactions, but I don't have it.
Oh hmmm I initially though you were referring to wild magic effects that had reactions, but apparently there aren't any... Though I think you mean "Bend Luck" and not "Tides of Chaos"; it's the former that uses reactions. But that only happens at 6th level, so isn't relevant for EA.
Anyway, aside from the subclass's randomness being tailor made for Larian, the Wild Magic table also works very well in video game format. The computer can do all the calculations immediately, instead of massively slowing down the game by a) remembering to have the DM roll on the table, b) finding which effect happens, and c) looking up the rules for WM spells/other complex effects.
