other commanders should be made more appealing rather then nerfing actually good commanders.
Not really. One should decided on benchmark commander for each faction and try to bring as many commander as possible to that benchmark.
In addition there are simply some combination that simply should not exist and Ele/ISU stuka/Il-2 are some of those combos that should not exist.
thats a much better way to improve diversity rather then nerfing stuff down
Again not really. Power creep rather high in over the years and it turn the game from strategy to arcade.