It really would help quite a bit with things if CG would release "demo" videos showing off which teams they envision us using to beat these waves. No need to dive into mods or strats like YouTubers, just a flat "here's what it looks like" video would help ease some of the "this is ridiculous, how can anyone do this??" feelings that many seem to have.
Seeing "CG approved" teams win would also encourage me to gear up those characters that I might not have thought to use. Maybe CG even knows of some oddball compositions that we (the community) haven't thought of yet that we can't try because we only get one shot per month to get anything at all and you don't want to waste your one chance at certain battles.
Separately however, it would be a HUGE boost to motivation if we could get do-overs for the battles. It's way too demotivating to know you only get one shot for something you technically spend a month preparing for. Even if it cost 50 crystals to refresh I would often pay that cost just to get another try if I see something in the battle that makes me think that different mods or just a little more gear would do the trick. It's hard to apply any lessons learned from battles when RNG and the passage of time are working so hard against us.
As it stands you basically have to go a whole month (during which time you might switch around mods for raids, TW, GAC, etc) before you can test your strategy again. Just being able to do one redo, or one practice run would make this feel far less crappy (maybe practice runs could be limited to just one wave?)
Show us what it should look like CG. You ostensibly know exactly what we should be doing, so throw us a friggin bone here.