I took four flights over the last few days, the first ones after the "new system". I decided to buy seats up front to protect my... knees, of course I did not do it happily.
Two of the flights (domestic) were absolutely full in coach, while two (non-Schengen) had free seats in the front section. I was able to do some stats on one of them (if there is a statistician reading this, please excuse my calling this statistics
)
I counted 21 people pre-boarding through the C/Gold lane. Of them, 8 sat in business and 9 upfront. This means that roughly 3 out of 4 M+B golds pay a bit more to have more legroom (that was an A321). On both of the non-full flights I had the seat next to me free. Since I was not planning of having food, this was almost like flying C on those.