Revert dem changes, find other ways to make SC viable instead. Maybe start with Speeders idk!
To be fair, a speeder buff would be very useful. As of right now, using them leaves very little room for mistakes, they barely outrange the units they are supposed to kite, so you need to micro them intensely to get any of their value and don't even deal that much damage. Maybe if they could shoot a little farther they would prove themselves more useful, but too much range and they would reach game breaking levels quite quickly (This is mostly based on PvE matches, but i believe it is still a valid take on the matter).