It also means that decks just have more rares in general, especially in Sealed. Nobody is really opening 12+ rares in sealed, but getting eight to 10 rares out of six packs is doable, and even in draft you more often play with and against rares.
There are a lot of effects that happen when the rare density goes up, and overall it's certainly put a lot more emphasis on high-rarity cards. You should aggressively take sideboard answers in best of three, and make sure you have a good amount of removal in best of one.
Another obvious effect here is that you wheel cards less often, which means you can't count on much coming back around. That's a shame, since wheeling something good for you is a really fun part of draft (and a nice reward for being in the right colors). It's not a huge deal, since it's mostly just an outgrowth of the previous point, but it is something I miss.
I think these are all pretty big negatives. Especially with sealed, I haven't played MKM sealed but I have been turned off from trying because of the new pack type. I really think they should have kept the Draft Booster and the Collector Booster, and got rid of the Set booster. Just put a random art card in the draft booster along with the list slot.