Yeah, there could be a logical explanation along these lines. Frankly Batman is overexposed in films alone, put aside cartoons and comics. If he was also overexposed with tv shows (most of which being sub-par) then that could potentially hurt the brand.Maybe they worry about diminishing Batman's impact on the Big Screen if he's on TV aswell. Although I don't know why that wouldn't apply even more to Superman.
Though Superman has a lot of exposure, he hasn't had near the exposure that Batman does in film and animated TV.