This TD meta is bad design as long as it counters every single vehicle. I'm fine with TDs countering heavy tanks - although this should be less easy (with range differences making it way too easy to kite currently). However, TDs should have lower rate of fire so they do not counter mediums as well. Right now, Allied TD is just the answer to everything and it makes the Allied game devoid of the same strategic choices Axis have to make.
Its a situation you can't really win and it'll always be about TD meta in team games.
In 2v2 and 1v1 the units need to be strong to counter what they need to without the need to get multiple, especially with their large pop cap and cost.
And you can't nerf it without lowering cost and pop to allow to get more, because now you will need more to do the job, which encourages spam anyway(as evidenced in the past).
If you nerf RoF, that'll also allow heavies to be used much more aggressively, panther included, because now it can stand in range that much longer, which again forces player to get more TDs instead of other vehicles to counter lower RoF.
Unless people will learn to use ATGs, AT infantry and flanks to keep TDs at range and counter them, people will always complain.
And yes, allied TDs are answer to everything, because there is literally no alternative, allies do not have cheaper, spammable TD that would be answer to med and axis always have possibility to get panther out, so a TD needed to counter it in anticipation is mandatory.
Both axis factions have Panthers, but they also have Pumas, StuGs, JP4s. Couple that with allied paper armor outside of british very late game and you have the answer why its like that.
Only soviets have SU-76, but that is still less effective then any of the axis ones against meds, especially post nerfs.