I am one of what feels like the few comp players that are actually open to this idea. This pretty much gives the freedom back to the players which is something I am 100% for. The difficulties you may run into, which I’m sure has been mentioned already are.
Defense just got harder. No more gibbing the engi/sold for a defensive reset etc. I think proper spawn waves are even more important now than before.
If I interpreted correctly, are you saying that the cocaine medic can now use a more mid range weapon? If so, that is an excellent change imo.
Something to keep in mind, with this change, Engineers will pretty much be an extinct class. To curve this, I would suggest engineers have 3 frag nades with the removal of frag nades from other classes. This will make them a very strong pick for defense (can also be abused on plant based offensive objectives.)
Do you intend on giving other classes special grenades? Smoke/heal for Medics, AoE Denial for Lts, and large disorients for Solds (please nerf flashbangs already?)
I don’t really have much to say but wow. Which is probably what you guys wanted to hear instead of bitching so congratz. 
I personally can’t wait to test this out.
(3 Sold 2 Med will be beast for attackers now.)