If you want to fix T4 the way to do it is this;
1. Panther is 150 fuel (with T4 being so insanely expensive the Panther shouldn't be even more on top of that)
Why do you have so hard time comprehending the concept of cost effectiveness and tech cost being indicator of TIMING, not performance.
2. Pwerer get's it's original amount of rockets fired back (16) and some more health/armor to reflect the fact it's actually a HT.
Its already more armored then Katy.
Drive closer for better accuracy.
3. Sturmpanzer IV gets better pathing and a hold fire button considering the only way to hit accurately with it is using attack ground.
Pathing fix, yes, but its accurate enough, attack ground only maximizes that accuracy.