I don't see any way of fixing the situation, either. Basi range is fine, it'd be dumb to decrease it for that one bsuit+painsaw. Painsaw range is fine, allows aliens to outbite. Can't increase range and decrease damage, not without dramatically reducing the damage, because then aliens wouldn't be able to take one on due to the much higher damage of painsaw.
Possible solution: have the left mouse button act as a "jab" function. You move the saw forward, takes about a second to jab and then 2 seconds cooldown. The jab increases your range to 64, which is the basi grabbing range, but only lasts for a short while (does damage for about 1/2 or 1/4 of a second)
Not only would that be useful against basis, it'd help out a bit in lots of situations.
But seriously, the best armour doesn't belong with the worst weapon you can buy. Either use a helmet and larmour, or save up for a decent weapon. (also, who uses the bsuit+saw combo and DOESN'T rush OM?)