The problem is providing a ground-based pilot with sufficient information to build situational awareness of the battle. Immersive environments seem to be the best tool, but that requires considerable sensory capability in the remote vehicle and considerable communication bandwidth.

This reminds me of the ongoing debate whether manned or unmanned space exploration is better. Each side has very good points. You can send remotes much farther than humans, and much more cheaply. But the quality of the exploration benefits immeasurably from the onsite presence of an adaptive human explorer.

I'm also reminded of Wernher von Braun's comment that a human pilot was the most effective computer you could put in a spacecraft, and how they could be mass produced with relatively unskilled labor.

But of course combat and exploration have different goals and therefore different requirements.