What makes using OBD2 system, so much better than OBD1

I had 20 yrs in auto repair. Got out in 97. So I never worked on the OBD2 systems. I also have a 46 dodge truck that has megasquirt MS2Extra. So I've been involved with things like this before. Just not OBD2... or the RE series transmissions ,just looking for some input. Thanks
If you have used the megasquirt systems check in with Matt Cramer at DIY autotune. There are a few guys who supposedly got a controler working for the RE trans.
You may have to use this to work though.
DNJ-DCF1
Read this for explanation on operation.

Chrysler 47RE info - MSgpio.com read only forums (Jan.15,2018)