Pep was a success at Barcelona, i already mentioned that. the team underachieved in Rijkards last season (they still lost only 1-0 on aggregate in the CL SF against the best team in the world at that moment) in the league, had a terrible run of results from January, from they loss to Madrid at the Camp Nou onwards. Guardiola got a great team yes, but it takes a coach to make any team function, same goes for that Barca. later he got an, on paper, improved team each year with Ibra, Cesc, Villa, Sanchez etc and kept the level of success until beaten by Mourinhos Madrid. he then, with that kind of achievements takes over Bayern and fails to get them to even one CL final in 3 years. i already said what i had about Jupp, the Dortmund he was competing against is much superior to the Dortmund Pep competed against. Lewa, Gotze, Kagawa/Reus, Sahin/Gundogan, Hummels, a good Subotic, Kuba etc. that team was the champion the year before Heynckes took over, while Bayern barely made the CL and that mostly thanks to Hannover losing 2 of their last 3 games that season AND because Bayern sacked LVG for the last 3 games. Heynckes made them a CL finalists in his 1st year, they beat a superstrong Madrid, the strongest one in Mourinhos time there, they lost the title in a close race to Dortmund and lost the Cup final. they didnt win anything that year which is a failure for Bayern but they improved ALOT from previous year. the year after they destroyed everyone so Jupp again took them to another level. in the next 3 years under Pep they looked weaker than that team DESPITE improving the team on paper each year. 3 years without a CL final is a failure, whatever way you look at it. losing 4-0 and 3-0 to Madrid and Barca is a failure. not winning the SC (a useless competition that top clubs actually care about nowadays) even once is a failure, especially vs the likes of Wolfsburg. losing the DFB Pokal final vs Wolfsburg is a failure. and lastly but most importantly, introducing his inferior playing style to the superior one they had under Heynckes, especially since the team was built to play that way, is a failure.
long story short, he was a success at Barca, a failure at Bayern. WC coach? yes. best in the world? nope