i really dont see where there is a question here. yeah it would make for a good fight, interesting for atleast its first half as the skills of each one of them plays out in some form or fashion but hands down Shatterstar.
I see it eventually coming down to close combat.. he can take a few arrows for the sake of a fatal blow.
He just has the overall advantage, and i dont think he walk out of it unscratched but he would be the one walking away from it.
i might be overlooking arsenal's capability but when compairing deathstroke and shatterstar as opponnents for arsenal they share simularity in physical ability including a healing factor but if memory services me correctly i believe shatterstars healing ability is abit more proactive than deathstrokes not to mention at first glance this seems like 'long rang' vs 'close rang' but shatterstar does have that ability to send those shockwaves from his swords. given it exhaust him but done at the right time it could be what wins if not just tilts things in his favor.