- in PT, clip gain can go to + 36 dB (Nuendo envelope cannot go higher than 0, basicaly is an attenuation curve only)
- the whole curve in PT can be adjusted without switching tools
- clip gain curve is always visible
- select a range of points and nudge up/down in level, or move left/right (like in Nuendo automation)
- range can be selected without switching tools
Plus 3 of those things you are missing in Nuendo and Pro Tools has.
So where do you see the limitations?