Like this:
Assault
-Assault Rifles
-Grenade Launchers
-Mobile spawn point
-Two grenades
-Pistol
Medic
-Shotguns
-Defibrilator
-Med kit
-Grenade
-Pistol
Support
-Machine Gun
-Ammo box
-Binoculars
-Grenade
-Pistol
Engineer
-SMG
-Repair Tool
-Rocket
-Grenade
-Pistol
Recon
-Sniper rifles
-C4
-SOFLAM
-Grenade
-Pistol
Shotguns for medics puts emphasis on the medic-ing and prevents the player from abusing the fact that he has a medkit. Hard to camp distances when you are limited to using a scattergun. More realistic slugs would allow greater range, but not to the outrageous level of accuracy and distance that BC2 takes it. SMGs for engineers serves much the same purpose, but I give them SMGs just so there's an excuse to put SMGs in the game. I'd be fine with giving them assault rifles as well. I'd also be fine with letting anybody use shotguns, but medics are forced to use ONLY shotguns. I feel having two grenades on the Assault class is compelling enough to make me want to play Assault. Binoculars on the support class would be for calling in a mortar strike to the commander, so that he can either direct fast air or an actual artillery barrage. Since support is support, I figured it would be his job to do that. I leave lasing to recon because that requires more sneaking than a simple phone call. Anybody can call in an air strike, but not everyone can get in close enough to lase undetected.
In addition, we might also reintroduce class-specific armour levels. Assault and support get extra body armour, Medic and Engineer are average, and Recon is light. It makes sense, because Assault and Support are the primary firepower of a squad and they are supposed to make an area safe for the combat engineer or medic to do his job. Recon isn't supposed to get into thick firefights.