Very true Patrick.
I'm repairing a hammer on airsoft ksc glock 17, I would think similar set up to the new umarex air pistol blowback G17 and you wouldn't believe the little parts and the 4-5 little springs in just the rear hammer assembly, it's testing my patience!
Now take a crosman 2240, doddle to tune/repair.
I also repaired a Umarex cp88 a couple of years ago and with the help of some online guides UBC/YouTube I managed it, but again very fiddly and time consuming.