No one wants speed improvements? Part of the reason for the core rewrite was to make C4D handle more complex scenes and be a lot quicker. As far as I know you're all still waiting. So for me, not that it really matters since I no longer use C4D my top 5 would be:
Faster / handle more objects
Bodypaint / UV tools replaced. Unbelieveable that the UV tools still haven't been replaced
Modelling tool enhancements e.g. proper symmetry modelling, Bridge tool enhancements, modelling fall offs.
Thinking Particles replaced. Alternatively admit defeat and remove TP and make X-Particles the default particle system. Do some sort of deal where users can buy X-Particles at a reduced price
Lower the price of monthly subscriptions. Given the world we currently find ourselves in with Covid-19 things are going to be tough financially for a few years. Unless the price comes down those charging hefty subscriptions could struggle. Blender is starting to look mighty attractive at the moment.