To be fair, had they not done so, they would run the risk of another club jumping in ahead of them. The deal was agreed prior to the semi's as well, so it isn't a case of Bayern just agreeing a €37 million deal to mess with Dortmund and Goetze's head ahead of final.
Would be intersting to find out if Goetze is a Guardiola signing or a Hoeness/ Rummenige/ Sammer signing.
I was going to respond in much the same way, Bayern had to negotiate and seal the deal so to speak, however, they didn't have to announce it when they did, or for months. ULtimately though if they didn't actually put the deal across and seal it, then Gotze may have gotten a higher wage offer and someone else may have sneaked in and done the deal with Dortmund. The problem being, multiple millions moving, accountants, managers, agents, people at the club who know, ultimately it was likely someone would leak it, an announcement kinda gets it over and done with, within the team.
One way, they try to keep it quiet but someone leaks a rumour about it and the days up to the game are all Gotze being told to keep quite but the team talking amongst themselves, ultimately out in the open stops a lot of gossiping, rumours and mistrust going on.
As for being a great game, meh, two great teams sometimes ends up being a crap game, it COULD be a great game, it has potential to be one of the best CL finals we've seen in ages but, who knows. To be honest Chelsea's defensive feats, the chances blocked, it wasn't massively high quality football offensively, there was some incredibly defending and it was an exciting game.