I think it's more a case that those resources that went into translating all the descriptions were moved over to the significantly more extensive Tips and Help sections that now exists. There's loads of organized tips for items, techniques, game mechanics, and a whole section that let's you pick a character or stage and gives info on some mechanics of them you might not have known about. There's a technique section that goes over game mechanics that have been present since 64/Melee like SDI/DI respectively and they finally decided to explicitly acknowledge them in-game, explain how they work and have a little video showing what it does.
Unfortunately, from looking around it seems most people don't bother with them. I remember when Hero released, there were poor saps that spent up to an hour doing Smash attacks over and over to get some idea what the chance of getting a crit was. They could have saved themselves the trouble by just looking at the Tips section for them where it clearly states it was 1 in 8. I imagine we'll go through this again where Pyra/Mythra will have some special property on an attack, people will notice it after spending a ton of time in Training, and think they're discovered some crazy hidden tech that's not hidden at all and is explicitly explained by the game if they bothered to look first.