Wrt the next manager after the next manager - as much as I loved Giggs as a player, I'd politely and respectfully ask him to join another club as soon as a new manager is hired, or maybe at the end of the season at max. In saying that I don't 'hate' Giggs, and I don't care abut his sordid personal escapades, just as I don't care about José's antics. No grooming or allusions of him being a future candidate, no nothing, no reserve manager - if he stays on as a coach he will forevermore be a noose around the manager's neck now that he's had the taste of managing United's first team, and maybe promised a managerial role behind closed doors. If he wants to stay, keep him in technical roles and tell him he's not going to be the next manager and will continue in the technical or executive side of the club like Sir Bobby, maybe become our Sporting Director one day if he has the right credentials and shows the capacity in administrative roles; if he wants to become our manager in the future, then he needs to go and spread his wings. It's not like he is Bob Pailsey who was an assistant for 15 years with no managerial ambitions of his own until later on, and became manager only when Shankly retired; or Fagan who was a reserve/ first team coach for 20+ years under both Shankly and Paisley; or Pep who was never promised the manager's job in the future under Rijkaard and only became a major candidate for the position under Laporta because of his excellent work with Barça B.
Thank you for your record-breaking service Giggsy, we love you and everything you've done for the club, you've been the spiritual successor to Sir Bobby; but if you want to become our next manager - then please go, and cut your teeth elsewhere. Infact, I'd rip a lot of the exciting setup and start building from scratch without a lot of links to previous managerial tenures - the club needs a culture shock to come to terms with the elites of modern football and the professionalism that clubs like Bayern Munich exhibit, and if we keep romanticizing the past and 'grooming' managers, it will never happen. If we get Pep or Mourinho, let's plan the future around Pep or Mourinho instead of presuming that they will leave in 3-4 seasons thus necessitating the 'grooming' procedure. If and when they leave, get the best manager around (this is what Bayern does, and it serves them well - they keep their ex-players like Rummenigge or Breitner in executive or scouting roles instead of forcing the issue with them as coaches or assistants or making them suffer delusions of grandeur). If Giggs proves his mettle by then, appoint him, but stop feeding him the dream now. We made a mistake by getting ahead of ourselves, and anointing him as a successor in the first place, let's not perpetuate that.