I don't think I would drop any of the units just change tactics to fit the new capabilities of the units. these changes will make commandos and paratroopers more useful for their cost.
I feel the real loophole abuse comes from Negotiating a war just to acquire a supply drop. Being able to negotiate to acquire a Province, ROW or share map Requires a certain amount of trust with with the individual involved.
you should be able to acquire a supply drop through diplomatic means not just going to war like moving a unit to the supply drop when you have Share map or ROW and if you acquire the province through a trade.
when you build paratroopers 1 is for when they are airborne ( needs an airbase or it becomes a convoy truck) the other is on land (like Infantry ) when in the airborne mode they can land anywhere in range and will attack the province as a ground unit after landing
Marines that have a much reduced Embarking Disembarking time Engineers to speed up building and Repair of buildings, Infrastructure and to destroy buildings of your choice. make commandos stealth at sea when stacked with a Sub
click on booster card Icon pick unit you want pick location you want it click on unit box at location to start. Your unit should show up Mobilizing in location selected
I don't think it needs to be a Gold Counterspy just imagine the effect of a golder using gold to destroy your airbase and he keeps getting captured by the counterspy
The best thing you could do is to not get locked up in Melee combat your battle ship can fire at a convoy all day and not take any damage save your sub for any ships that try and get away if they scatter or use your sub to lock up the convoy to prevent them from moving