I have used all three i.e. ATARI 800XL, ZX spectrum and MSX type machines. I still have an MSX in working condition. The best architecture was that of MSX, having Microsoft eXtended BASIC. I practised assembly language on MSX.

I would love to recall old memories and join hands with you if you are really interested in making an 8052 based computer. But I wonder if we would be able to get chips like TMS9902 (Video Display processor), AY3-8910 (Sound chip) and of course 8255 :-) or implement those functions in modern chips.