Vikings are more expensive than Mutalisks (which have an easier time mitigating Parasitic Bomb), and they are about as expensive (although 25 cheaper on gas) as the primary air-to-air units of the other two factions.
Thatās not really a relevant point though.
Parasitic Bomb has a radius of 3. It takes quite a lot of time for Vikings (which are slower than Mutalisks and much squishier than Corruptors) to clear that distance. Considering the Vikingsā speed and health, they are arguably the most vulnerable combat unit against Parasitic Bomb (Mutalisks are 45% faster with similar health and fast regen, all other air combat units are tougher, etc).
The point is that Parasitic Bomb is powerful enough against Vikings that they do not remain a reliable counter against Brood Lords. Terran is better off resorting to Thors (which happen to be cheaper per supply than Vikings, if you actually care about cost, but also get hard-countered by Vipers or Infestors used properly), or Ghosts.
Repair is not overpowered. Repair costs resources (25% of unit cost, just like in WarCraft III), and the repair rate is based on the repair time stat (which is almost always equal to the build time).
SCVs are vulnerable while repairing, and they obviously arenāt mining while they are doing that.
Storm doesnāt seem good when you use it against Ultralisks either. AOE spells generally donāt have the damage to kill the gameās toughest units in one or two casts, because in order to do so they would have to be blatantly overpowered against everything else they can hit. Parasitic Bomb does have the largest radius and highest damage of any AOE spell though. Nothing else even comes close.
As for Battlecruisers themselves. Battlecruisers have a short timing window against Zerg where they are viable because Zergās strongest counters arenāt available yet, but Zerg is still usually able to manage them with Queens and Spore Crawlers.
After Zergās other counters (Corruptors, Infestors with NP, etc) become available, Battlecruisers usually fall off quite hard. They more or less donāt become viable again unless you can safely build up a large fleet (something limited by the shear number of resources, time, and starports needed for this); and even then, Zerg can technically deal with a Battlecruiser fleet with enough Infestor-NPs and Corruptors.
Considering the rest of your content, I doubt I will respond to you again. It is not healthy to waste time with someone so biased.