Not a really big fan here of Poch's. I think his teams play dirty football, his style is reminding me more of his fellow Argentine Simeone than, say, Pep or Klopp. Also his recruitment is questionable imo, which admittedly may or may not be in part Levy's fault.
The pros include the fact that he seemingly had a positive impact on the development of the likes of Son, Kane, Alli (as patchy as his form has been, Poch at least got one relaly good season out of him), et al. While guys like Son and Kane were always talented enough to reach those heights, he arguably raised the performances of the "lesser" players in the squad, mainly by implementing a functioning system, an advantage he has over someone like, say, Ole. Plus hes as close to guaranteed Top 4 as it's gonna get for the foreseeable future and also is able to work with what he has at his disposal.
Therefore my ideal plan would be to get Poch in on a relatively short contract (2+1 or something, a policy the club should adopt anyway given our recent "success" with managerial appointments) to reestablish us in Top 4 for 2 seasons running, which imo is his ceiling. I see Poch a bit like Big Sam, but for Top 4.
At that point we A) should be able to attract higher caliber players again and B) re-evaluate our manager situation with the likes of Rose, Nagelsmann, -insert random hype manager- potentially available. If Poch is exceeding expectations, fine, keep him, if not, go next.
I get it, we all were used to Sir Alex, we all want a long term manager, but this is exactly the sort of sentimental crap holding the club back.
Maybe we should go with the times and employ a more Chelsea-like model with shorter contracts while planning managerial appointments in advance, according to which manager would suit us most at a given point of the teams development, while also giving us much needed flexibility in case things go south again.
Should a manager perform well over a prolonged period of time, we can always extend him long term, I don't think any manager in their right mind would leave a successful Manchester United.
TL;dr: Get Poch on a short contract in order to bridge the time until Nagelsmann, Rose etc become available. Don't do long term contracts and extensions before they aren't deserved. Simple, really.