That is true and that's why I would take him back. Trusting youngsters and building a team and system is something he is great at.
He did fail Bayern though. As others have said, he wasn't brought to win Bundesliga nor did he do anything that any other good coach wouldn't. Now that you mentioned Van Gaal he built the team in worse circumstances and took Bayern to CL Final. So he basically did more than pep.
In terms of influence I think Van Gaal still outworks Guardiola. I mean all the things he contributed. Bringing in Robben (whom I personally consider one of the best wingers of all time when fit, but you might find that exagerated) and Ribery + some others, promoting Müller, moving Alaba from CDM to LB, and of course he was the guy who brought possession football to Bayern. The system was very flat in the beginning, teams figured that you can shut down Bayern simply by having 2 defenders man mark Robben and Ribery who were carrying the team.
Guardiola did very similar things, just to a less extent, bringing in Coman, Costa, Vidal, Thiago and Lewandowski etc (the latter would be an almost logical transfer though as he was worldclass and a free agent, I guess every Bayern coach would have gone for him), he also promoted Kimmch, just not to the first team yet. He didn't really evolve Bayern tactically, some thigns got better, others got worse, in the third year defending aswell as scoring crosses and set-pieces got better, but he didn't reinvent the wheel. At barca many people think he just inheritated success, but truth is that Barca looked like they were done before he took over. He sold crucial players like Dinho and Eto'o when everyone thought "wtf is he doing", bought Alves, Pique, Masch, promoted Busquets and moved Messi to the center. Also took over Aragones Tiki Taka and perfected it at Barca.
Van Gaal and Guardiola are both massive coaches with great and bad periods, but when they resign they always leave great teams behind that another coach might have tons of fun with once the tactics are right. Van gaal will do the same with ManUtd, even if they hate him now. Possessionbased football, brought Martial and Depay (don't know if the latter will click though), promoted Rashford, will eventually get fired soon, but in a couple of years United will be succesful again and the fundament of this is laid in their current shitty campaign.
Messi with 7 km , neymar 9 and suarez 9 = no tracking back = no runs made in the side nor in the front , we want to win games with "pure skill " yeah right good luck with that Buddy .. this is 2016 , every high level team has skilled players , if you want to take advantage of your lil extra skill , than you have to work as hard as they do for your skill to prevail. we have to push ourselves physically more ( obviously bayern too )
