It's probably way too late for this, but I'll throw it out there anyway. Would it be possible to have 2 autogen sliders, one for buildings, and one for trees? Maybe give the user the choice to balance between the two types?

I think it would be possible to do it at this time. It would need a new entry into the CFG file and a redesign on the graphics options menu.

As you say, way too late for that...