Any reason why? If they want to standardize the timings and cost, giving each faction a "T5" tech with unique costs to offset their other tech differences is pretty much the easier/best way to go about it.
Implementation time, apparently.
So you are in favour of deliberately unbalancing the game? Before OKW and Soviets needed the same amount of fuel to rush out Tiger and IS2. At least in that sense there was balance.
We do not need requirements like full tech but 11 CP for heavies and adjusted AOE so they don't wipe as much and aren't as insanely OP overall.
I'm in favour of fewer heavies. Making the heavy rush not viable for three more factions is an improvement in my book.