EMP isn't something that kills Protoss, it's something that makes the matchup even. To get MMM and Vikings you need starports with reactors, barracks with reactors, and more barracks with tech labs. It's very gas heavy and the tech isn't instantaneous ya know. Feedback is almost as useless as snipe is on ghosts.
Mules are terrible. Terran is always at an economic disadvantage. Protoss players using chrono boost can produce more workers, Zerg players can produce multiple drones at once. Each of these mechanics let your mineral income grow linearly, whereas mules cost twice as much energy and are only temporary boosts. IMO mule should be an upgrade that combines 2 or 3 SCVs (like HT to archons) and it should take about 5 seconds, and the mule should last forever. Helions can harass very well, but they can only kill zerglings, drones, and probes. If you block your ramp with 3 roaches, they can send a billion helions at you, but you can most likely hold. Also, if you spread your army, helions are worthless trash.
The balance right now is pretty good, but Terran is definitely at a slight disadvantage IMO.