I like both 'I'm Not Mister Mxypltk' & 'Dave' theories.
I just think about the pre-crisis Hal returning, just like the Silver Age Superboy and Earth 1 Superman. I know we didn't see Hal go with them but I just didn't like what they did with Hal in the Emerald Dawn mini. I was rereading some old Waid Flash and JLE, Hal came across as some out of touch lame joke telling....joke! That's not the Dude I grew up with!