I'm a long time Reason user (since 1.0). Left Reason at v8 (and almost stopped making music) and just got back with an upgrade to v11.
Seems like the Drum Sequencer Player could be enhanced a bit.
1. Display the velocity value in the same way probability is displayed.
2. Probability could have an "every nth hit" feature like Elektron sequencers. A probability of 1/4 would be "first of every 4 hits", for example.
3. More than 16 steps per track or pattern chaining. I'm aware of tricks to switch between patterns, thanks to this video