Make Ohmwrecker's active function like the old summoner spell "Garrison"

for those of you who don't know, Garrison was an old summoner spell for dominion that would temporarily either reduce a tower's damage by 80% if cast on a enemy tower OR greatly increase a tower's Attack speed when cast on an allied tower.

Ohmwrecker already has a similar effect on enemy towers so why don't we give it a similar effect on allied towers? It would expand Ohmwrecker's niche, making it useful even if your team is behind and it's balance could be easily tweaked by changing exactly how much Attack speed it grants an allied tower.