I don't think PV is the best tactical manager in MLS (probably top 5, but a notch below Tata and certainly Vanney). But I do think he would clean up Arsenal's act quite a bit and get them playing hard, which is what they need as much or more than anything.
It would likely be the best hire they could make, as I think Tuchel, for example, is not the right type manager to follow someone like Wenger. Damnit.
ETA:
If he gets the offer, he has to take it. There's literally no choice.
1 - He'll get a big-time multi-year guarantee, especially as he can leverage having to leave a first place side (or nearly) mid-season.
2 - If he doesn't win a single game as manager, he would still be a homerun hire for most any MLS or Ligue 1 club or anywhere in between, and that new contract would surely pay him more than what he's on now.
I don't think he's irreplaceable for us right now. I do think changing mid-season makes it really difficult. That said, you can't begrudge the man if he gets a shot at top 15 worldwide gig in his profession and he takes it. But we will. And there's nothing wrong with us doing so, as we're fans/supporters and by definition, maniacally and rightfully and openly biased. I understand you leaving Paddy. But I will still be pissed.