oh and mushrooms, block placers can place tree sapplings but not mushrooms

Could be a lack of imagination on my part but I'm not sure what this would be useful for, what uses do you have in mind?

A couple farms and vehicles

Vehicles are impractical with Block placers as slimefun machines do not integrate with movecraft. You would have to replace the block placer each time you moved.

i use them and its very practical you just have major skill issue

then again the main purpose for this suggestion is for a couple farms i want to make but due to the limitations as to how block placer works, its not attainable
henceforth, vehicles is not the priority