I think we can all say Sanguine Blade is quite powerful. OP that its already been hot fixed down to 80% from 100% and increased gold. I think its safe to say later on in the future this item will be reworked or completely nerfed to the ground if not treated properly.
Having the passive of attack speed and movement speed on constantly is quite broken. It really should activate when only 1 champion is nearby, rather than having it active all the time.