high on the goodness-o-meter

1. plenty of registers
   because more registers is more gooder!
   
   
   • 2 index registers thus more addressing modes
   • alternate register set
   
   
2. non-multiplexed bus
   with easy to decode bus phases
   and built in refresh phase for dynamic ram
   
   
3. separate memory and I/O address spaces
   
   Allows full 64k for memory
   and 8 or 16 bit I/O addressing
   
   
4. backwards compatible with Intel 8008, 8080
   (see plays well with others)
   
   The incremental step from the 8008 to 8080
   allowed for software re-use
   similar to the way x86 is still a thing.
   
   Historically, IBM made their bread & butter that way:
   upgrade to new model of mainframe
   but keep those legacy applications running!
   
   
5. expressive CISC instructions
   
   Remember, this was a time of the CISC mindset.
   Programmers were still hand coding assembler
   since compilers / higher level languages were still too slow.
   
   This was a time of feature-itis:
   adding features was advantageous.
   Kinda the opposite of RISC where
   

   "Perfection is achieved,
   not when there is nothing more to add,
   but when there is nothing left to take away"
   —Antoine de Saint-Exupéry