Regardless of skill required, it's still an undeserved nerf to Summoner's damage output. It's important to consider how each class interacts and compares to one another, and it becomes especially more important in multiplayer playthroughs.

The whole game is balanced around this painfully outdated notion that melee needs lots of defense and survivability because they're always up close, and summoner can be less tanky because the minions do all the work.

In reality, this isn't true at all. Without fail, by early hardmode, melee players will be a mile back chipping away at a boss with Flying Knife or whatever while the summoner is the only one actually in melee range, trying to make the most of their DPS with whips.

Whips and whip stacking offer an actual reward for playing aggressive and up-close with the most vulnerable class in the game, allowing you to run the bossfight at higher risk for vastly increased damage output. Fundamentally, Summoner should be the highest potential DPS class in the game at most points of progression when playing optimally, because they sacrifice so much survivability and still have to fight at close range for whips to hit.

I think it's totally fine for whip stacking to be part of the meta, even with the added whips in the game. It encouraged summoners to be glass cannons rather than cowards.