Ok well first off Elder kai said that the earing fusion was superior because of the no time limit, he never said it was stronger. his quote was "instantly your bodies will bind together and become much stronger, my kind of fusion" which makes it sound like he's just explaining fusion not saying its stronger.
Also fusion creates an entirly different perosn it dosen't favour 1 person.
As for saying DBGT Gogeta dosen't count because its filler, well all I'v gotta say is Gogeta is filler in general.
And Vegito wasn't playing around he was luring Buu into absorbing him, so realy he was getting straight down to buisness. But Vegito would win because they would be stalemating for the 30 minuits then Vegito would kill Goku and Vegeta.
Gogeta killed Janemba straight off, probaly because if he played around he was worried goku and Vegeta couldn't fuse again, and in GT all Gogeta did was play around.
And Goku and Vegeta are equal in fighting skill, if they weren't Goku would have kicked the crap out of Majin Vegeta. Gohan aint that godd of a fighter, he mainly beats people cause he's so much stronger.