Like extremely low agility, selfdefeatingly slow turret which cannot track the circling medium tank, lacklustre combat blitz, and very soon even the critically nerfed back armmor ? ...
Its mobility is amply compensated by its armor and firepower. And it's still a turreted tank, so the mobility isn't that bad since you can traverse the tank and the turret together. ( without talking about the "sparehead" ability )
Although, if your Tiger II is annoyed by a " circling medium tank ", then you should ask yourself some questions.
It really doesn't need kind of bulletins you mentionned, it's already a formidable tank. A veterancy bonus is good, and maybe a cost reduction, but no more.