Again I didn't say it made Rogue an omega mutant. But regardless, I still think her powers could have adapted and grown to make her into a possible omega candidate with the way she was being developed. Having the ability to recall every power she ever absorbed (and not being limited to only one at a time) puts her pretty damn close to having "unlimited potential" with her powers. And who is to say her powers won't develop further enabling her to absorb any being she comes in contact with. Jean started off moving pencils for pete's sake and look at her now.
So I summarized her powers, point? Regardless of "potential" when Rogue absorbs another persons powers she has access to their powers and their memories on how to control those powers. It's the same thing as when Emma inhabited Bobby and pushed his powers passed his perceived limits. Emma didn't have his "potential" yet she was still able to control and use his "omega level" powers.
Like I've said, I'm not saying her absorbing an omega would make her an omega just that it would temporarily put her in the omega level power range. I know that being an omega is all about potential ability, but I also think there is a clear difference in power levels between alphas and omegas. Rogue wouldn't technically be an omega but the power she would be using would be on that level. Same way people look at folks like Storm and Magneto to have powers on the same level as omegas.
In all honesty, I'm sick of omega mutants. There are too damn many that should be or could possibly be. Everyone always talks about potential well geez then let's make every darn reality alterer an omega because you can't get much more unlimited potential then being able to change reality on a whim.