I'm really surprised you'd want Mourinho mate, any of the hopes you had for us playing attractive football and a proper 4-3-3 would die with him in charge, not to mention he's a clown.
Well what can I say, I've always been kind of a closet Mourinho admirer (from afar), and even wanted him to replace Fergie in 2013. He can be petulant yes, but a lot of it is physiological warfare (barring this season, the Tito eye gouging and the Eva episode - the details of which are still pretty murky). Do think his reputation for being the baron of shite football is a little undeserved too. His teams have never finished outside of the Top 3 in the league in terms of scoring (and that 3rd position was from his first season back at Chelsea in 2013, apart from that he has always finished in the Top 2). His first Chelsea team played some lovely football at times, as did Porto. Even Internazionale could be exciting - defeating Barcelona 3-1 at San Siro was no mean feat and they were pulsating vs Chelsea at Stamford Bridge with Sneijder running riot. Real Madrid scored 326 league goals under him in 3 seasons. Barcelona scored 320 goals in comparison, and they had Pep at the helm for the first 2 seasons, including the 2011/ 2012 season when Real Madrid established a new Liga record for goals in a season that stands to this day - with 121 in 38 games. One might argue that anyone could get that level of production from a team boasting the talents of Ronaldo, Benzema, Di María and Özil, but Barcelona had an even better attack and Madrid still managed to outscore them. He does deserve some form of credit for that. Even the draw in Madrid vs United was quite open, and only a sensational performance from De Gea kept them at bay.
He is pragmatic first and foremost no doubt about it, but if he has the personnel to play attractive football, he won't necessarily shackle them unless the occasion demands it - big European matches, title deciders, against key rivals and the like. It's just that those kind of bigger matches are more highlighted, so he has gotten the label of a bus parking anti-football expert. Also, he is quite fluid when it comes to formations. Porto played a sort of diamond with Deco as the AM behind two strikers, Chelsea played a 4-3-3 with Lampard as the attacking box to box and Essien as the defensive box to box with Robben and Duff out wide, Internazionale alternated between a 4-2-3-1 and a 4-3-3 with Sneijder tucking in and Milito, Eto'o, Pandev up front. So the hopes for a 4-3-3 wouldn't necessarily die with his appointment. With Madrid, he was almost forced into a 4-2-3-1 because of Özil too. He will play the formation which will get the best out of the available personnel, so nothing is set in stone from that perspective.
Also, a couple quick points:
1. He will be up for it. We know what happened when he was sacked at Chelsea for the first time - his Internazionale tenure was really special, and I think Mourinho will be super motivated to take the United job. Remember when he was at Porto and linked to the Liverpool job before joining Chelsea. He said something to the tune of - United and Liverpool are the two teams he would love to manage in England because of their history. And I think United might bring the best out of him, really do. It might just be a perfect storm situation with a club that needs guidance coupling with a decorated manager who's beleaguered right now, and at the nadir of his career.
2. Chelsea's performances this season were not all on Mourinho. The players had quite visibly given up for some reason, and I suspect there were a lot of background politics going on with multiple people trying to one up each other under Abramovich. Plus, a lot of Chelsea supporters I know said that they had overachieved last season, and were set to regress following a summer where they didn't make substantial improvements in terms of adding quality players to push on. Far too much of the blame is being leveled on Mourinho which I think is a bit unfair.
3. Despite his failings at Chelsea, IMO Mourinho is still a Top 3 manager. He has a fantastic body of work and it's a bit early to downgrade him. Some class Simeone alongside him and Pep, others Ancelotti; but IMO Mourinho has the best resume after (or at par with) Pep. Too many times people rely on emotion which stems from a dislike of José, his personality, or the notion of his dull brand of football; but rationally speaking, he is a winner (6 months doesn't change that), and might just be the best choice, especially now that Pep and Carlo look set to join other clubs. And what went on at Chelsea doesn't really affect that stance, because we know too little to form a concrete opinion.