I understand your numbers but I think eliminating the event balances the game too much in Allies' favor.
Personally I have only used paratroops as support, using the doctrine only paratroops would condition the manufacturing queue, that is already a small punishment.
It would be a shame to eliminate the invasion of Greece by minimizing it, because it is one of the most fun, if it is not achieved on the first turn it can be very complicated, I like the idea of deciding how much I want to bet to avoid it when I play as Ally.
The solution could be the CVs, I think the idea was that they would work as short-range fighters but in practice they do not, they do not intercept paradrops or tactical bombers when they attack friendly troops within their range, I do not know if technically it is possible that they comply this function but it would certainly multiply the tactical options.
Even so in 40 if the axis goes with all its force, it can always knock down Greece in one turn, but at the cost of delaying other operations and a waste of troops efficiency and waste of train and transport ships.
And this is a cost to take into account, not just the economic one.
Finally a madness, there would always be the option for the UK to invade Greece before Axis and fortify it, although I imagine it would leave the Middle East unprotected, hard decisions, which is the fun thing!