Penelo was my melee, with a katana in her hands.
1-HP<40%, cast Cura
2-Ashe, use Phoenix Tail
3-Penelo, cast Haste
4-1 party member, cast Vocal (cures Silence status)
5-1 party member, cast Brana (cures Darkness status)
6-1 party member, cast Stona (cures Stone/Countdown to Stone status)
7-1 party member, use Alarm Clock (item that cures Sleep status)
8-1 party member, use Restorative Medicine (item that cures Confuse status)
9-Penelo, cast Protect
10-Penelo, cast Regen
11-1 party member, use Panacea (aka Remedy item)/1 ally MP<30%, use Ether
12-First visible enemy, attack)
#11 is off, because sometimes Penelo would go and use the item to cure Poison status and stuff. I switched it to use an Ether if a character's MP fell below 30% for bluemax's vid/so it was something turned on.
It's not an absolute perfect setup, like if Vaan and Penelo both got Confused at the same time, but that rarely, if ever, happened. More or less there are a couple of ways to cure certain status, like if Penelo was silenced, Ashe could bust out with using just the item that cured it to fix her up. I placed Esuna and Panacea low on the list so hopefully someone else would use the cheaper MP cost spell or item beforehand.
More or less, I was pretty much ok through the game with these; I of course had different HP values and Cure-family spell depending on where I was in the game, but the above setup is what I used on the last boss in that video I made for bluemax without using the controller, so it worked for me throughout the game without doing all this so-called 'constant changing of gambits for many bosses'. It's not super advanced; pretty basic actually. I just added to the Gambits, I did not have to change them at all, more or less. But I fought very few mob hunts last time, too, nor have I fought a whole lot of them overall (maybe 17 or so in total).
The 'easy to miss' thing I was talking about is how to cure status ailments. I think you start with the '1 party member' gambit "if" statement, so you can use that to cure stuff long before you get the "if party member is poisoned"-type ones. Like with the self-buffs, the character will only use/cast the status fix when the ailment that can be cured with that spell/item has been inflicted. Penelo will not constantly cast Vocal or use Alarm Clocks with that setup.