I get the concern, but I don't feel that would happen. Maybe it's just a weird comparison, but right now, I'm kind of viewing Froslass in Xy like I did Nidoqueen in BW2.
So, quick history lesson for those of you not around for BW2 Nidoqueen era, Queen made it damn hard to use Stall due to the fact that it had incredible coverage, great power, and due to Sheer Force, could hold Life Orb for no cost. She was also hard to wear down since she was immune to Toxic. When Nidoqueen left the tier, Stall was viable, but it wasn't an overwhelming force in the metagame.
With that out of the way, take a moment and look at Froslass. With the ease that it sets up Spikes, it makes life really difficult for defensive teams as they generally are greatly pressured by Spikes. Thanks to the offensive nature of Froslass's team, it can be difficult for the likes of Gligar, Golbat, and Togetic to get off a Defog unless they're able to find a way in on something that simply can't get past them. Froslass is an amazing Pokemon and does wonders to help offensive teams thrive in the tier. But on the flip side, it puts a serious strain on any defensive-minded team and makes it much more difficult to use them effectively. Even on the balance team that I've been using thus far, I've been having some major issues with Froslass, so much so that I've tried using Jolteon over Heliolisk just to outspeed the damn thing and keep it at a single layer, even though my primary sweeper is ass-weak to Rhyperior (something Heliolisk easily preys on) I'm really starting to lean toward it needing to go, but maybe I just haven't played enough games yet.