I understand the reasoning behind this:
1. Noone uses the weapon modules at all, because they cannot compete with the other modules, with which they share places.
2. More consumables people use, more CBs they will waste in a match, making grinds take longer, which might motivate spending MC instead.
Therefore splitting the module slots into 3 separate categories will motivate people to use more consumables, since you either use those slots for this kind of modules, or you keep them empty, thus putting yourself at a disadvantage and at the same time will promote weapon modules for the same reason.
Obviously, I am not on the same boat with that theory - Weapon modules suck, period, and (with a few exceptions that are marginally useful) will not see much use anyways.
Consumables, on the other hand, will most likely lead to a higher number of strikes per match, and the last thing we need is a strike spam. If it motivated more people to use UAVs, I might be happy about the change, but... no, it won't. In reality, it's just an extra consumable, or an extra 'Mech module for the competitive folks.
Furthermore, we get nerfs on 'Mechs like the Jenner-K, who was considered the weakest of the CB Jennys and got an extra module slot in return for less weapon slots. Nerfing the module count on the RVN-3L and AS7-D-DC can at least be somewhat justified, as those were the best variants of the chassi (thanks to that beautiful piece of equipment).
Well I sure hope you weren't using more than 2 'Mech modules on your Jenners (or most other 'Mechs, for that matter), guys. I was...