I'm trying to evaluate Stash, specifically with an end goal of migrating from a very legacy SVN setup as well. I'm new to this team, and was not involved in the inital SVN layout. Anyway, long story short, its a mess. I've used svn2git, and the rather generic Atlassian docs, but, well, GIGO, I suppose. I see that pull requests can go across repositories (and assume, automatic triggers could, too). Maybe I just need to build things out by hand.
I guess, I'm wondering if there is a more full "worst case" import scenario?