this has been suggested many times before you have and i dont think you will find a lot of "allies" on this one
Oh? Never saw it suggested on here before. But I have not been as active lately so may have missed it.
I suppose I can see why lack of advocacy might arise with some old players who have already spent inordinate life-time to develop their formations piece-wise by active tinkering every-day to get it "just right". There's often a generally prevailing "sweat-equity debt comeuppance" mentality/attitude in these genre of online games as well as a paranoia about loss of "edge" to newer players who didn't work as hard (and walk to school in the freezing snow) like they did.
Oh well...
On the Job Training, baby!
Honestly, giving people who don't understand the mechanics of Banish events a practice arena will not help them at all. They need to interact with players who do well, study those forms, then unplug and use their brains to try and figure out why top players approach it the way they do. Once they understand that, practice is moot. It's back to OJT.
As for practice fights vs other players...that took some of the fun and mystery out of the game. I'm not a fan.