WOOHOO a new puppy!!!! Man there have been quite a few lately, keep em coming!!!
I too think it's totally about the individual dog. Don't get me wrong there are a lot of breed specific things, but just like people dogs have their own personality. I too have a dominant/aggressive breeed, german shepherds. My first one was a male, Navarre, and now I have Issabeaux. I suggest getting everything you can get your hands on about Rotti's and READ!! Get some basic training and behavior books too, read them BEFORE you have anything come up.
And when things do arise, post a question!!! You'll get many different responses, some you won't agree with (but in the end may try anyway!) and some you'll love! That's the great thing about this site everyone has something different that has worked for them. Navarre my male was an absolute TURD when he was young (I also used something like the roll that Lin talked about) but became a perfect gentleman and absolutely LOVED in the neighborhood. Issy, just turned one last Sun, and she is the energizer bunny and tries my patience from 7am-10pm!!!!
Some things that I wish I would have known with Navarre when he was a pup that may have helped. When you pick the pup up to hold him/her and they struggle, don't put them down until they have calmed down and are still for a bit. Really this applies to anything, if the pup doesn't like it and you give in, they've won. If your watching TV put them on their side or back and rub their belly, if they struggle quit rubbing but don't let them up, when they quit struggling rub the belly some more. This is a version of the roll but when they are pups and you do it just because, not when they get in trouble 1) it's not a "discipline", they may be nervous at first but 2) they learn they can trust you, cause when they are on their backs, in their most submissive position, they get tummy rubs!!!
Sorry this was sooooo long!!! Good luck on your pup, and we want pics as soon as he/she come home!!!