Id like to see Ableton crerate a new set of plugins designed for finer audio tuning. The sort you'd place in the master channel before rendering a tune, not really full blown mastering FX, just something a little closer than what we have.
1. A really nice accurate EQ with a large interface and different eq types, something capable of mixdown precision. The eq we have already is really good but not really accurate enough for finalising a mixdown.
2. A good multi band compressor limiter, maybe with warming options if desired.
Again, not really what you'd class as mastering FX, just better than what we alredy have for finishing.