Signet Build running it's course
Signet build is a pure leveling build. It does ridiculously well till lvl 50/60, at which point it starts dropping significantly in performance, but still remains strong enough that it’s usually the most convenient “idiot proof” build for leveling purposes till lvl 80.
However, by lvl 50/60, if you drop a few silver coins on proper level armour/trinkets/weaponry you can start changing your build into whatever build you want to do. Rifle/GS is definitely a viable weapon choice, and your build will depend entirely on what you prefer… You can build more offensive or defensive. Most people will agree that, for leveling purposes, a full offensive build does better, but it’s really your choice.
The key thing to remember is that, for the most part, your stats come from your gear. Your traiting is more about the minor and major traits you want to pick up. Just look at the traits and check out which traits you want to use, and don’t feel obligated to put more points in a tree than you need. It’s perfectly OK to, say, go 25 points in a tree if there’s no other major trait you wanna use.