The thing that boggles my mind with this whole thing - and with previous weapons debates - is that if the game isn't broken, don't try to fix it. You have no idea the number of times I was told I was "trying to stop the game from evolving" when I brought the ESEA whitelist to UGC - but the growth of that league that occurred while I was the admin there, and has continued since, seems to absolve me.
It's just like the debate with replay in baseball. Just because the thing is available doesn't necessarily mean it should be used unless it will demonstrably improve the playing/viewing experience as a whole. That's the line we, as a community, really ought to take with most of our rules and unlocks. Just because the quick-fix is available and even if it is nerfed, it doesn't add anything of value to our game, in fact, even if it were some non-reality where the quick-fix wasn't a big deal, I would still argue against its inclusion because our game fundamentally revolves around uber and kritz (with kritz being decidedly less useful than it was due to arrow building already and the demo nerf).
I would encourage you *not* to back out of the league if you've already signed up - you're surely not the only ones who feel upset. Talk to the other team leaders, just like I did in s14, and explain to them you have no interest in running xyz weapons, and that you won't run them unless they do. If you find a team that refuses to abide by that agreement, refuse to scrim them, ever. It works very well, particularly in IM and the upper reaches of open, or invite. Since those teams often have to be pretty picky about who they scrim, and if all of your ideal scrim partners wont play you, you wont be playing a lot of useful tf2 lol.
While we're at it, I'll air another grievance of mine. Pre-arranged scrims outside of invite are hurting the community. Stop, please. Use discord or IRC or anything. Imagine how many teams don't form because mixes don't happen as often anymore, or teams that simply can't find scrims and become discouraged and quit. It's demonstrably bad. I understand if you're an invite team or the tippy-top of IM not scrimming any random team, but everybody else should take anybody who wants to throw down. Not to mention if you're really grinding out scrims it will be easier to scrim longer if you can do it as we did in ye olden days lol. It also makes leading a team considerably easier because you don't have to arrange everything in advance, and you don't have to worry about finding ringers in a rush. Plus, you wont spending 20 minutes+ of your scrim time waiting on the other team to show up to a pre-arranged scrim because their scout is out with pneumonia unexpectedly. It's all positives. Hell, back in the day there used to exist these things called "scrim teams" who were just collections of older players who just showed up in IRC a few days a week and gave *really* good games fairly regularly - but that's gone completely now as well. I even personally tried to resurrect Dheroes but we gave up in part because we couldn't find anybody to scrim lol.