Counterspelled Booming Blade

[Psyren]

No, you need rules, or situational limits. (“Hey do you think the King will mind if we torch the throne room with a fireball? Yes? Ok”)

We have rules. And implementing "situational limits" is also known as "designing an encounter."

There is something about needing to inflate the damage in order to halve it that I find aesthetically displeasing.

I'm not "inflating" anything - I'm using the printed Improvising Damage value from the table in the DMG, which you're supposed to use for things like jumping into a volcano vent.