I understand your thinking that E+TMZ "is Class G if you are squawking". But apart from getting into a semantic debate, there are surely some significant differences:
1) unlike Class G, you need to be absolutely sure you can maintain VMC throughout your time in that airspace
2) if you go in there not talking to ATC, you are wholly reliant on your transponder working, but you have no way of telling whether it is or not
3) if you're an unverified squawk, AIUI ATC will give their IFR traffic 5nm or 3000ft separation on you; but if you're speaking to them they may be able to reduce that to 1000ft vertical (above!) which could make life a lot easier for them
I agree though that the plethora of airspace types that has developed is increasingly confusing.