In case you missed it, there was a new Banned and Restricted announcement impacting a bunch of formats, including some Historic changes. You can find a full list of banned and restricted cards for every format here. There are two main changes:
Memory Lapse being moved from “suspended” to “banned” was to be expected, as I don’t think there has ever been a Historic card that got suspended and subsequently unsuspended. Memory Lapse was far from broken, but they probably deemed it to be too unfun to play against, as nobody likes to get their spells countered. This is also why you don’t see cards like Stone Rain or Counterspell in Standard anymore. If you invest a lot of time and resources into building a cool deck, the last thing you want is your opponent stopping you from doing your thing.
Memory Lapse is at its best when it’s stopping cards that are more expensive from resolving because every time you trade up on mana, you’re gaining an advantage. I would say that the format actually got a bit faster with the addition of Modern Horizons 2 cards like Dragon’s Rage Channeler and Unholy Heat. However, it’s true that lately, midrange decks built around Inquisitor Captain and slower control and combo decks like Jeskai Control and Creativity have been gaining popularity, so the format is definitely not as fast as I was expecting.
Banning Memory Lapse makes the Jeskai decks worse, which I believe is an overall good thing for the format, because even without it, those decks are still at the top of the metagame in terms of win rates.
You can replace Memory Lapse with cards like Essence Scatter, Censor or Negate, but those cards are very situational. Control decks already have access to a lot of other cheap answers like Portable Hole and Lightning Helix, so if their flexible two-mana counter gets banned and they’re forced to play something more high variance or more expensive, that’s probably a good thing for the health of the format.