With the importance of the PG position and Lillard's athleticism I think you can make a case he has a higher ceiling than Roy did. But Roy reached his so we'll have to wait and see. Also, to the Lillard-pickers who said they enjoy watching Lillard more than they ever did watching Roy: I think that's a little bit of recency bias talking. Fact is it's probably a tie. Every one of us was just a gaga for Roy then as we are for Lillard now.
As for the post about Lillard's classmates who may have higher ceilings (Beal, Barnes, Davis), I think Drummond was a glaring omission. In fact I think it's to the point he's the only candidate. I could be wrong about Davis, but I just can't think of anyone in that mold being a superstar. Could he be a slightly better version of peak-Camby? Definitely. Barnes and Beal could be nice players, perhaps developing into the Rudy Gay of Roy's class as players who always seem like they might have the upside to surpass the R.O.Y. but can never quite get there and settle in as fringe all-star candidates.
Drummond, on the other hand, is what Oden was supposed to be. To me he has shown flashes of Shaq/Dwight that are impossible to ignore. I wonder if Detroit "knew" something the rest of us didn't about him (as in, have him top 3 on their board), or whether they just lucked into being the team on the clock when the risk/reward favored taking him. The fact that they didn't trade up suggests the latter. In which case, I would give anything to go back in time and trade from #11 to #9 by any means necessary.
