Imma rebu-ttal here. Roshi will probably carry people further in this game than any new ninja that'll be released. His scaling passive allows him to be used endgame and he's paired with many ninjas that come into the meta. For the amount of scrolls he runs you, he is well worth it. God forbid they give him skillbreaks. On the flipside of this argument though, he is not a one man army, especially if you're within the lower end of the bp then he gets destroyed.

For anyone, regardless of when you start this game. Do not pull in Sage, never pull in edo (made this mistake), do not jump straight to Jin. Kage treasure is your best friend. Bigger pool of ninjas which allows for flexibility and better team formations. The odds in Kage is fairly even although some would argue that Mei is not as common, but I see them everywhere. Also being azure fang, she is who you want. Once you get a a few banner ninjas then jump from that into Jin treasures or cloud, if its here by then, depending on what you need. You can even save for GNW treasure after you finish with Kage if that's another treasure you want to go after in the future (never hurts to be prepared). Kage ninjas will just help with story mode, arena, survival and even sage.