This is not a wanted swap ad (yet).
Would my A1200 be worth to swap for an A4000 ? This is the spec:
Amiga Technologies A1200HD
20GB 2.5" Hard drive
Blizzard 1230IV with 64MB Fast ram
Indivision AGA 1200
I think so anyway.... nice 1200 system. I think including the Indivision makes it a great deal for an A4000 owner to consider... Probably the speeds are pretty comparable if that is a 50mhz 1230 because a stock A4000 has a weak 040 implementation. I personally would rather have your A1200 (but i'm a fellow A1200 owner)

good luck with whatever you decide! I think going A4000 over towering the 1200 is the right decision if thats what you want..