Yep master league offline and online are still in. The old players from the older pes are even agents! Just don't tell Venkys.
MyClub is a really awesome mode. Fifa has ultimate team. Pes has this. Instead of buying/selling, you get random players from balls, like a lottery. It's great.
Best for files last year was pes world. Will be so much easier this year only having to download/upload a couple of files.
As for the stadiums, I think they said a lot of them are coming after launch. Also weekly data updates! (Last year was a joke, the game didn't get its first transfer update until after everyone had already done the one by one edit and guess what the update did....)