^How so? If it can work in other mediums, why not live action? It all depends on how it's written. They tried Robin before and it didn't work because Dick was already an adult. There was no room for a father/son dynamic. Using Robin is a chance for Bruce to dial back the neurosis a bit, and explore new elements of his character. If we're going for a more fantastical universe, then why can't Robin be used?
Because even in the fantastical BTAS I had trouble buying that Bruce would ever put kids like Barbara or Tim Drake in constant, real danger like that.
No matter how well-trained they are, these are still some serious (and often supernaturally strong) bad guys they're going up against, and who knows
what random, unexpected thing could happen in a fight.
And even in BTAS it often seemed like a stretch that these kids were as effective in battle as they were. I can only imagine how much MORE unlikely that would appear in live-action. Unless you first dumb these villains down to cartoonish levels to make it seem like a fair fight, and then you're right back to Schumacher territory.