First, a bit of background.
In the starting years of league, there was a summoner spell called "Promote". It worked quite like a hand of baron buff, or more accurately, a banner of command active. Promote only affected cannon and siege minions, and made them super OP. BUT, that's not all.
So the entire team ran Promote and made one super push that couldn't be stopped.
Then it got removed and reworked into banner of command.
Banner of command has been gone for a while now, and a few people missed it as it was quite iconic. Riot has plans to bring it back but they don't know where to start. (Might be wrong.)
Right then, onto my idea.
300 second cd.
Give the targeted minion a boost in its stats, increasing with average champion level in the game and game length, giving the champion half the gold the boosted minion earns. Can't stack with itself OR hand of baron.
Super minion - boost resistances, move speed and attack speed.
Siege minion - boost attack range, speed and damage.
Caster minion - boost attack speed, damage and hp. Removes the debuff "Phreakish Gusto" which takes 70% of its health per tower shot, and replaces it with "Gusto" which takes 45% of their health per tower shot, after 20 minutes of game time.
Melee minion - boost resistances, move speed and hp. Removes the debuff "Gusto" and replaces it with "Insert_imaginitive_name_here" which takes 30% of their health per tower shot, after 20 minutes of game time.
In case you didn't know, the debuffs "Gusto" and "Phreakish Gusto" means that per tower shot, they will ONLY lose 45% and 70% of their health, per tower shot, respectively. No more, no less. Same goes for "Insert_imaginitive_name_here".
Now obviously I haven't given any real specifics (apart from cd) like how much the stats increase by because it shouldn't be so OP it changes the game, but it should be there to help close games that have stalled.