You're trying to argue with a troll who thinks that anything added that isn't Ultimate is a waste of resources...yet 99% of people couldn't care about if people cleared Ultimate or not.
Honestly, I'm less bothered by the actual cheesing nowdays and more concerned about the mentality it's breeding.
If there's a laughably easy way to clear the duels and give everyone a mettle buff, it puts mental pressure on people to do it as the jobs were reasonably balanced in terms of how quickly/easily they could clear the duels prior to Flare Star being added and there was no objectively "best" strategy/build for dealing with them.
I personally am trying to clear the duels "normally" before I attempt the cheese strat on any of them, but I can't help but feel like I'm depriving people because I know I could easily get the win if I simply abused RDM and buff stacking.
Let me ask all of you a related question: have you ever done raids in a game like this? There's so much cheese that it is ever-present. The playerbase truly loves their cheese. If the developers try to take away the cheese, they must be crazy and they should instead just embrace the cheese. If someone doesn't like the cheese, they deserve to be mocked. Every time a new raid (or anything farmable really) comes out, people will go out of their way to look for the good old cheese. When they find the cheese, they gleefully dig in until they get more of the same and find triumph in cheesing it all over again.
Most people enjoy the rewards more than any journey along the way (which is unsurprising considering what they are doing in these places, farming). So to avoid people jumping down your throat, cheese it. CHEESE IT!
Why not just make it so theres a cooldown on lost actions when you swap them out, and switching out lost actions removes all buffs/debuffs received from them?