I'll give you the laptop comment, that's fair and a Natami laptop would rock. As for the A1200 form factor, it's great as far as it goes but once you start expaning it gets a bit tight. You can squeeze in networking and an optical drive but a faster than 030 CPU and RTG card leaves very few options in the original case. It is do-able of course but It's easier to go for a tower. I guess it depends on what you use it for and if you have other Amigas to use for RTG games etc..
Don't get me wrong, I still have an A1200 wedge myself but it's my "classic era" machine so to speak. '030 is enough and wireless networking is via PCMCIA. I also have a pet hate in the form of external drives, too messy for me, My desk is cluttered enough without adding to it. However, an opinion is just that and it all comes down to taste in the end.