I guess it's relative. I don't require a schematic on the Ring with white papers giving all the specs,... but I do like the fact that they are "made" not pulled out of a blue butt as needed.
As far as I see,.. there has to be an upper limit, otherwise one guardian could do the job of all the GL's between moves in a chess game with his off duty blue friend,
Or with an planet GL, You could have an area of responsibility much much larger than what is posted because it's canon that the planet has so much willpower that it multitasks on an immense level - Encoding rings for future use, playing shrink and help-mate to mentally damaged gl's, doing hundreds of things for the corps w/o strain.
V.
Wow, I actually see what (I think) you mean. Odd, since you didn't actually say it and it involves a very interesting assumption.
A) If the ring has unlimited potential, then a person with infinite willpower could put on the ring and remake the universe. Notably, however, they would not have enough charge to do so... perhaps they could effect a whole sector?
B) If the ring had no upper limit, then the creators, the Guardians, would not have an upper limit either and could do everything themselves. That's the assumption, and I disagree, and think it's perfectly possible that the rings are more powerful than the Guardians just as cars are faster than humans. They don't use rings because they don't want to get their hands dirty, it seems. I personally think it would be very cool if one of the 10 new laws included an Oan Lantern for Sector 0. 3601 Lanterns. Heh.
C) Mogo could patrol multiple sectors if the ring had no upper limit? Perhaps, perhaps not. Perhaps he could patrol his whole sector from his stationary orbit, which, techinically would be necessary since he is a sector GL. Furthermore, he does this while multitasking on an immense level. Is it possible that he could do much more if not multitasking? Perhaps so... but what's the problem with that? What were you thinking by "Much much larger?" and did you have any references for this size assumption?
Every way we try to slice it, the original concept is for the willpower of the individual to determine the limit of that individual's power level. Changing that is something very new and very limiting, storywise.
In short: No, Varient, there does not have to be an upper limit. A lack of such would not create any of the discrepancies you have pointed out.