Wait, so you think it a problem he doesn't need strength? What??
By not needing strength mods, Gauss has more space to build what you really want, like duration or range, to crank those offensive stats. With 0 strength mods he can reach 100% DR, something no other frame but revenant can make a claim to, and gauss also gets energy back on hit, making efficiency mods also not required
The rocket projectiles are not supposed to be your main damage tool. That would be thermal sunder. Furthermore, Gauss is easily the best weapon platform in the game, with the highest fire rate buffs in the game, and some of the base melee speed buffs to boot.