Seeing that there’s 2 digits (and therefore a range of 0-255 ticks) this would make much more sense. Still, i personally think the best thing would be a separate command for both delay-n-rows and delay-n-ticks.
For relative tempo changes: In impulse tracker, the tempo change command also has a lower limit of 0x20 (32), while T0x decreases by x and T1x increases by x. Imho this is the most optimal and useful setup.
If this and the sharp / flat thing are fixed, i would buy renoise immediately. Not joking.