Ambulances have a set of defibs inside them. TBH I would not be buffing other classes just take the recon back a notch. Support gets 8 plates, Assault gets the ladder which I have seen used very well, Engineer gets the aim guided rockets that snipe people just as well as tanks as well as the ability to open safes. Support gets ammo, quicker no defib revives and 8 plates which is huge in many games where you are low on plates from fighting and everything has been looted late game. Only recon is a notch above the rest