I respect your decisions, but let me say my opinion as a person who mains the sniper class.
First off, I'll explain why snipers are allowed to use shields. Without shields, they'll be like gunslingers. Second, it's too much to let SinX users have a shield on the offhand. (Also, it'll mess up the + damage in Double Attack, I think.) And just like my homie Collin [sartorius19] said (which is true, he wrecked my SinX before) there are alot of ways to counter the bolts. Assassin Crosses deal TONS of damage especially with SB, and you could say that Assassin Crosses are like glass cannons with a bit of defensive options like Cloak. TLDR: No. -1