Well to explain the logic we used behind the current rate of fire, we took a look at the "fluff" of the bolter in all its iterations to see what its supposed to be.
Within the background material (specifically 2-4th ed 40k) we felt that it was more akin to a micro-rocket launcher rather than a fully automatic weapon as a lot of the artwork and other games show it as. The Firewarrior Bolter we felt was about right (and one of the only good things about that game).
Also for balancing reasons we (at the time, the ROF thing was added later, and it does some damage calculations that reduce damage for greater fire rate) liked that the marines had to place there shots which meant that the nids were not just greeted with a hail of fully automatic gun fire.
The addition of a secondary burst fire mode with cooldown is in the discussion stage, a bit like the RS1 bolter.
Next time were testing anything ill get that RoF plugged into the console and see how it looks.
http://www.youtube.com/watch?v=6k3crc7-LRY - made a vid of it for clarity.
