The Stuka is significantly less effective vs blobs as opposed to other rocket artillery such as the Panzerwerfer (Due to the Werfer's much larger area of effect) or the Katyusha (Due to the speed at which rockets arrive on target). If you are managing to Stuka a blob your opponent is terrible, as the linear nature of the Stuka's projectiles, and the slow speed at which it reaches the target, gives an opponent more than enough time to react, particularly if you're positing that they are able to simply dodge AVRE and Sturmtiger shots perfectly. You are also required to predict well in advance of where the blob will even go.
This linear nature is what makes it effective vs team weapons, however. They are far less responsive, and you are able to place shells precisely where the weapons are (Multiple weapons, generally, due to the length of rocket's linear placement). The Stuka is an anti-team weapon platform, not one to deal with blobs.
Also, again, UKF don't have the Stuka.
The AVRE and Sturmtiger are Meme tanks not because they are not "really needed", but because they are extremely cheesy and expensive, and very all-or-nothing.
You anecdotally having "no issue" with a lack of turret doesn't mean it isnt a weakness of the Sturmtiger, and buffing the Sturmtiger turnrate simply does nothing to counter several of the weaknesses I've suggested. I hope you realise that "Five vet" on OKW units is no longer necessarily them being "Better" at vet5 than another faction's equivalent unit at vet3, right? Its primarily a flavour thing... and on top of this, reaching veterancy 5 on a Sturmtiger takes an absolute ton of XP, you arent getting a Vet5 Sturmtiger in every game. Hell, all vet5 on the sturmtiger does is allow it to do what the AVRE can already do (At no risk, due to lacking the Sturmtiger's "lol oops you got abandoned ))" if it's shot while reloading)
So are you saying you only use and save stuka barrages for team weapons because "the infantry will just dodge it".
UKF don't have stuka, no shit sherlock. That's why they are a different faction with different units and gimmicks.
They are not really needed because they are expensive, had a lot more alternatives.
so you're point is just buff sturmtiger so its better than avre. It is ok it will just cost more fuelto build than it will had ever before