Coalfuel was pretty useless, since all it really did was fuel the fuel powered jetpack, which no one really used anyway.
My suggestion is bring it back, and just make it burn for more in the generator so that early game when you're burning coal, you actually have a better form to use before you start on green gens/nuclear/other non-early game power source. You could also bring back the old coalfuel processing chain but make it end with coal being a liquid, which could be burned in the semi-fluid generator for even more EU, and to power the fuel powered jetpack. But since it was a liquid, it wouldn't be able to go in the jetpack if there was biogas there (since before, the jetpack was either filled or not filled, so plant and coal materials could be mixed together). You could even bring bring back superfuel, as a mixture of coal and plant matter, and potentially power the jetpack with that instead of just coal fuel or just biogas.