Not quite sure I follow what you're getting at here.
The Pedal modline doesn't take up a key (touchpad) on the Softstep. You can put a pedal modline on any key, and also have 5 more modlines on that key to send whatever MIDI messages you need. It in no way takes away or limits the amount of keys available to you. It does take away one of sixty modlines (66 if you count the navpad), but that shouldn't ever be an issue in normal use cases.