"critical attack blocker" is, roughly speaking, just another (quite large) HP module which you put into drone slot; handheld "shield" (actually limited-durability plate of metal in shape of shield) could serve the same purpose while using one of FOUR side weapon slots.
"Leech" is repair+damage at same time... which is actually pretty interesting tactical choice, which we can add for more balance between defence and offence.
regeneration drone is just regen module you put into drone slot. Cooling one is more interesting - but I am not sure if that useful, compared to irreplaceable repair drone (for defence builds) or attack drone which gives very much needed Damage Per Turn (for offence builds)
not sure abt what "shield booster" is. But if this is drone that improves your shield quality (for example, by cutting in two energy/heat cost of damage absorbed), it might be alternative for repair drone in terms of defences.
actually would be nice to see top weapon "Drone pad": it uses top weapon slot and also have some weight, but gives extra drone slot. Ability to put drone into weapon slot would be balanced by extra weight of Drone pad, plus we can forbut people to use two or three Repair Drones at once (which would be obviously broken) - still it would create some space for trying out those additional supportive drones.