Ground STFs can be fun. Wish they hadn't killed the incentives to play them, it's impossible to get a game in the queue, so can only play when there's a premade around that's up for it...
They take 3-4x longer than a space STF, just increase the rewards to compensate, and might get some action again.
If you haven't noticed, Cryptic hasn't given out more than 480 dilithium for any event in a long while. 960 dil in STFs are already an anomaly. While I agree with you that they should give more for ground STFs, asking Cryptic to give even more rewards is pretty much an impossiblity.