I think that Sivir is underplayed because of her weak ult. I was thinking of some buffs for it and I thought of 3 different buffs. one could be ignore unit collision. If some crazy person started sprinting at me I think I would step out of the way, so why don't the minions. the second is it could be like in mario where you get the 3 mushrooms, so she can activate her ult 3 times, but a weaker buff. the third option could be that she and her team get a move speed buff, then little move speed pads spawn, if an ally step on them they get the move speed buff.