each disc speed rating roughly corresponds to a speed range. exactly what that speed range is depends on the nose down. more nose down = less speed is needed to generate intended flight path X.
as a rule of thumb, to "work" the disc you need to be able to exceed the upper bound of the speed range. if the disc falls below the lower bound of the speed range (given the nose angle) it will begin to fade. this is why OAT happens when players throw discs that are too fast for them. they don't generate enough speed to get the disc to turn naturally and if they don't turn the disc it fades off too much, too early.
you can somewhat offset speed requirement with stability, but there's a term for fast discs that can be thrown for players who don't have enough power... and that term is squirrely.
consistent distance and control is yielded when players are able to generate speeds beyond the upper bound of the disc's cruising speed range. there are some cases where discs have an incredibly high upper bound and a significantly lower lower bound (teebird, roc, wizard come to mind here) and for these discs it's more a matter of being able to go well beyond the lower bound.
i find it's easier to gauge average driving distance than it is to gauge actual flight speeds (although many of my approximations on actual speed are fairly accurate). i've used this to approximate minimum distances needed to get consistent distance from a disc (although this doesn't necessarily reflect "workable" power levels). basically, the ability to turn a disc over from a pured flat throw is the minimum measure that a disc is a good choice imo (with a few exceptions).
drivers that turn at ~250' of power: sidewinder, cheetah, leopard. archangel, etc.
drivers that turn at ~275' of power: gazelle, polaris ls, XL, cyclone, EL
drivers that turn at ~300' of power: JLS, roadrunner, valkyrie, beast, XS, xpress
drivers that turn at ~330' of power: wildcat, rogue, viking, surge ss, avenger ss, TL, orion ls
drivers that turn at ~360' of power: wraith, SL, orc, flash, orion lf, surge
drivers that turn at ~390' of power: destroyer, force, crush
the "ideal" is something you can throw pure that will turn on a flat throw and fly straight with some hyzer on it.
there's only a handful of drivers that are anomolies in that they are fairly straight but need power in the 400'+ range to see any turn. the Teebird (480'+ range), Starfire-X (430-460' range), X2 (460'+ range) would make that list.