it really does depend on the game, but in my mind whenever a publisher/developer states that about their upcoming game it most often means "we're dumbing it down so we can reach a wider demographic, so we can earn more money and possibly capture call of duty's audience" and that can displease the fanbase of whatever series, and/or work in the game's disavantage by getting shallower and as such, stray away from unusual or "complicated" ideas that would be interesting to see.
However I'm not saying a shallow or simple game is bad, but again it depends on what you're going for, if you're making an rpg more shallow, then it works against the whole concept of role playing games, while for example a handheld/ios puzzle game will do much better as a simpler and less deep experience. Action games can be shallow but still fun to play, but it can sometimes leave the game unremarkable unless you have something unique that it thrives upon.
let's take an example like Journey, the recent masterpiece (imo) from thegamecompany, it's so simple, minimalistic, shallow even in its gameplay, but simple things like sliding in sand, interacting with the second player to overcome obstacles and the way that world and vague story is crafter working together with the stunning visual composition makes the game remarkable despite its "shallow" gameplay.
Now we're discussing the gamedev/publisher quote here, so I'll just say I'm opposed to it, because that exact quote imo usually means "we're making this game dumber so we can cash in"
