Well to be honest I don't, which is why I said they should take a good long look at them. I do know that the Civil War Black Panther suit wasn't as form-fitting as they wanted, which led to them touching it up with CGI in post. So if you're not willing to do any post-production touch-ups, I suppose there's a drawback.
If there are better alternatives, I'm happy to hear them. But even with the advancements made with the BvS/JL batsuits, they're still heavily-padded rubber suits (albeit textured go resemble fabric). I'd like to see something new brought to the table.
Really depends what kind of look they're going for, but the obvious non-CGI solution is to simply produce a slightly slimmer muscle/body suit that can be covered with a textured "fabric" similar to the BvS/JL suits or some kind of new material when the time comes.
A good example would be the Sam Raimi Spider-man suits (at least in the first film), which actually did have understated padded/sculpted musculature in places suit beneath the "spandex" but still created the illusion that it was really only the actor or stuntman's actual musculature. The end result was a suit that appeared to be completely form-fitting and skin-tight, with not even a crease or any "bagginess" in sight. Also allowed the actor to be completely agile with full range of motion.
That was nearly 20 years ago, so I have to believe that they can take a similar concept/method and effectively translate it to fit the Batman aesthetic when called for. Snyder was obviously going for something different in terms of depicting his Batman as more of a hulking brute and bodybuilder, and his sculpted Batman suit fits that's aesthetic while still allowing the actor/stuntman to be pretty damn agile, all things considered. That method can eventually be stripped down and refined a bit to develop a new Batman aesthetic that more closely resembles a gymnast or martial artist as opposed to a bruiser or bodybuilder.
I really don't think CGI is the solution to every problem, or this "problem". Yes, a CGI-enhanced Batman suit could work and look cool, or it could be jarring and obvious (see: Cartoon Spider-man in Civil War and Homecoming). I'd much prefer to see them build on the huge advancements they've made with the BvS/JL suits since the Burton/Schumacher/Nolan days as opposed to reverting to CGI. (We've already reverted to a CGI cape in most instances, which has its positives and negatives in terms of execution)
Batman is also supposed to be a "real" guy wearing a "real" suit made out of seemingly real-word armor and materials (as opposed to Green Lantern or Black Panther who is decked out in the mysterious "vibranium") and I do think it helps to put the actor in a real, fully formed suit on-set.