As of 04/03 points for time improvements (different from rank improvements), will be removed and you will be unable to accrue points in this manner.

This is for two reasons:
A) The multiplier table which stores how many improvements you have, has reset to 0 for all players TWICE resulting in lost points and annoyed players.
B) This can be exploited to gain an unfair advantage over other players.

A more indepth explanation as to how this works;
You completed map surf_beginner with a time of 2:05 and gain 5 points Rank 1/200
You completed map surf_beginner with a time of 2:00 and gain 15 points Rank 1/200 (15 bonus points for time improvement)
You completed map surf_beginner with a time of 1:59 and gain 15 points Rank 1/200 (15 points for time improvement)

This could have been done an unlimited amount of times to gain a stupid amount of points, so this update was ABSOLUTELY necessary to ensure a fair competitive environment.