With questions like this I always feel like the people asking for a higher ceiling are only looking up, while they should also be looking down.

The DPS spread as shown on fflogs suggests there already is a very significant skill ceiling.
Even on savage (which already has the best players) there is a very significant difference between a 50th percentile and a 9-th percentile player.
And that is not even counting the players that are not skilled enough to do savage content.