Being able to go straight to the most recent new content in each discussion is crucial. In my view, this is the single most important feature in forum software.
I doubt whether anyone would have a problem with the whole discussion being displayed so long as you "land" at the point where new content begins. Being able to simply scroll up from that point of landing to previously-read content would actually be better in my view than what we have now.
However, if what you said here -
> Topics will show all (something that is taking me a while to get used to, I like just seeing the new content).
implies that you go to the top of the topic and you have to find where the new stuff starts yourself, I'd be somewhat concerned.
Assuming that you do get taken automatically to the new content, then there's the matter of whether the new content remains treated as new until you've actually displayed it.
In some forums, new content flags persist until you at least display the particular discussion, which is (IMHO) the correct way to do things.
In some forums, new content flags kind of time out after you visit the forum, regardless of whether you've read the individual discussions or not. So if you don't have time on a particular visit to see all new content, you're unable on a later visit to identify what you missed on the previous visit. And that's not good.
Perhaps some detail on these aspects would be reassuring. Or not!