What-if Videos are not actual proposal.
Sovereign Battlecruiser has two attack options; to switch to ATX Laser Battery or Mini Yamato Gun.
For this experiment I used 3 Sovereign Battle Cruisers and reinforced its health with filled 100 supplies with Han’s mercenaries.
With Full upgrade and all in Significant others mastery.
I pitted them against Brooding Corruption and Devouring Scourge
I enabled them to attack with all weapons.
The result was that SBC is much suited for dealing with swarmy flier units but the improvement is questionable as Han’s Mercenaries or Horner’s Lesser aircraft can easily deal with swarmy units while SBC are specialised to snipe very tough units. Besides, all Horner’s Air Combat units (Theia Ravens) are limited by 300 sec cooldowns.
Its performance would likely to stay the same even with this buff.
In this video I increased the Mini Yamato to 10 (from 6).
It seemed appropriate as all Yamato cannon related spells have 10 range.
Other than that, I see no problem with them.