This isn't a general question,nor really a technical  report,but a conundrum nevertheless.

Though anyone could respond here with an opinion,only the designers really would, should, might know the answer.

Mystified ,when I started playing, maybe new starters still are about enhanced versus sustained procedures.

I have been playing long enough to know the difference, but based on curiosity and a bit of basic testing, I want to know what is actually enhanced in enhanced attacks, and why sustained attack is so called?

My understanding of the word sustained is continuous at the same time, and as enhanced  is indicative of an increased benefit a switch of names seems to have happened. 

Yes you might say that the current sustained attack is continuous,but it's delayed continuity, connected, or linked would seem to be a better description perhaps?