Thank you for this awesome feedback! It really means a lot to me when people take their time to write out the pros and cons of my projects, now I know how to move forward!
Regarding the balancing aspect: I totally agree. I didn't have a chance to playtest a lot, but after submitting and taking my time playing the game, I noticed that the cog was losing integrity way too slow for it to matter at all and that the coal consumption time (the time it takes for one piece of coal to be used) is too low, causing the furnace to easily not overheat.
For a future update, i'd probably mess around with those numbers a bit and also add some more tasks to do around the other cabins :P
Thanks for the feedback and for playing my game!