Widow Mine - smaller splash or only half damage vs air. You simply can't go air vs them and fly over ground because they vaporize shit instantly, unless you have inhuman reflexes.
Emergency Boosters - requires research from startport tech lab or armory. Third base for toss is harder to take in PvT than PvZ, which is retarded. I'd make siege research again too, since it's not doing the intended job.
Those would be my best guesses on the changes.