In Starcraft II, Terran is OP in comparison to the other two races.

I'll simply be addressing each of my opponents point, as proving he is wrong would be proving balancing opposed to me trying to say another race is simply better. First, my opponent says that scouting isn't enough, and that it is nearly impossible due to lack of alert. In all honesty, a player who isn't attentive enough to see a medi-vac incoming DESERVES to get hit my it. There are many many ways to avoid it, which I will present now. 1. Early scouting with an observer or changeling. Simply knowing that your opponent is creating medi-vacs makes the entire point of dropping nearly useless. A smart player would then invest in photon cannons or spore crawlers, which make the Terran drop not only impossible, but HARMFUL to the Terran player. On wrong step can lose an entire medi-vac of units. 2. Early aggression will always beat a Terran who is trying MMM drops. Medi-vac tech is costly, as the opponent usually can't invest gas into Maruaders or Tanks as they're trying to get the drop as soon as possible. 3. Protoss and Zerg have ways to drop and harass as well. Warp Prisms and the Nydus Network are under-used, yes, but are very effective as they both offer no real loss of units if they fail, unlike losing a medi-vac full of units. Next, my opponent brought up helions and Reapers. Easy way to deal with them? Move workers off of the line. Simple. Reapers and helions cannot simply chase the drones or probes because any smart player would rush their army to fight. Neither unit can cause significant structure damage as well. Yes, Reapers have strong anti-building weapons, but they would only kill a building before an army reached it if they were in mass. A mass reaper army would be the absolute weakest army in the game, making any of their opponent's attacks 100% successful. My opponent's Tank argument is mainly invalid as well. He assumes that the opponent would simply wait for him to get 20 some tanks and they push out. The reality is, that the Terran Army cannot simple mass units until it's time to push out. As stated before, Warp Prisms and the Nydus Network would make bunkering down nearly impossible. Also, the most defensive Zerg unit, the Roach, can easily withstand Tank damage, and as soon as the Tanks are down, Marines are practically useless again them. The Protoss, again, have the Immortal, which takes minimal damage from tanks and does extra damage to them. My opponent then brought up the fact that the Terran player could invest in a Planetary Fortress. Here, the pros and cons of choice come into effect. When a Terran player builds a PF, they are not building an Orbital Command. They lose high economic power to due MULES and they cannot scan. Granted, the Terran player usually does not change their first base into a PF, but only one Orbital Command makes any cloaked attacks extremely powerful due to lack of scans because they had to go exclusively MULES to make up for the lost minerals. Also, PF's can't aim up. Easy counter? Air units. Since the Terran player is basically choosing to play defensive, the Protoss or Zerg armies can simply just mass units. Roaches and Immortals again take little damage and can easily destroy PF's. Again, if Terran was simply better than the other two races, then why would pros use the other two races at all? Terran mechanics are just simpler, but that doesn't make them better. High risk and high reward is the basic principle. Sure, you can simply load 8 Marines into a medi-vac, but what happens when you lose them all to a few roaming Phoenix due to the fact that you were simply scouted in the early-mid game? Thank you.