@WireBender You clearly don’t see them perform at all, ain’t you?
The reason Zealots are weak in SC2 is because a power surge happened.
Even though Zealots is among the small number of units stay relatively the same stats-wise, the buff other units received make them much weaker.
Marine by default has +5 Health and +1 range compare to default BW marine. They can later becomes +15 health and take 4 attacks from Zealots to die in comparison to BW taking only 3 hits.
Medic in BW is also much weaker than Medivac. Number 1, they are ground units so they will occupy space that could have been filled with Marines, effectively reduce the firepower of your critical-mass marines squad. Number 2, they are not at the same speed as Stimpack Marines so they can become a blockage or not being able to catch up with the army while Medivac is a flying units they can catch up with the faster marines because they can fly over un-walkable terrain. Number 3, while being x3 the price of Medic, Medivac can use afterburners to boost speed and they double as transport so you can micro them to void enemy incoming projectile when needed.
Think about it there are very rare for a unit to have more than 10 damage in tier 1 the only exception is Dragoon and not anything else. Hydralisk in BW is basically 5 damage and deal 10 against massive. In Tier 2, there are almost no units that deal 20 damage except for Siege Tank in Siege Mode, Guardian, Goliath AA, Reaver, DT, Archon, Scout AA, Wraith AA. Zealot in BW have x2 survivability in comparison to SC2. Zealots in BW also have less dangerous enemy because all Terran infantry are below 60 Health and Zerg are below 125 in Tier 1 and 2. Zealots themselves have enough DPS and Health to be both a tank and Damage dealer.
These roles are severely weakened in SC2 when Terran has a boost in Infantry Health with Elite units such as Marauder and Hellbats.
Ghost in BW is stronger than Ghost in SC2 because they are not made for DPS. They are spell casters what kind of idiots use BW ghost as Damage dealer? You use them to kill Zerglings? SC2 Ghost are much stronger in term of durability and offensive capacity but also lack the most OP ability in the entire game.
Psi-storm in BW are also +50% more damage than Psi-storm in SC2 if i remember it correctly. They only do not stack with each other but with how low health BW units are their damage are a nail in the finger.
Firebat in BW has concussive damage type in short they deal only 2x2 damage against large unit, 4x2 against medium and 8x2 against small. With or without the stimpack, Firebat can’t compete with Hellbats deal 12 damage up to 30 against light. Feel free to throw in 3 Firebats, i doubt they can be as strong as 1 hellbat in term of effective damage after minus all the enemy armor value and unit size.
And yeah, you are correct about the tank. For BC, i must say the reduced damage per attack are more severe than the attack speed boost SC2 BC received. SC is a game where higher attack damage are always a more welcoming sight, given how the damage was calculated. In a Front fight, SC2 BC is a flop but they sure have better Tactical use.
Nuke in SC2 is less damage but after Maru’s Nuclear winter show, i must say Nuke in SC2 are more useful in term of tactic. Even with the reduced damage, the only units that survive a nuke in the face are all expensive units and most of your army are not all Expensive but rather cheap units that will die in 1 nuke. Rather than spending double the resource +8 supply to overkill, SC2 Nuke deal less damage but still within the kill-threshold and is very useful at forcing enemy away. They basically much better, the only downside are Ghost is +25 gas and +75 min.
So good try @WireBender, at least you give all you know even though they are only half good.