I'm surprised no one took a notice of this and it's been eating me since I read November solicits.
I'll start from the beginning;
1) He was the first Titan Wally went to during Rebirth, even before Dick. It went like this; Boomerang, Cyborg, Nightwing. Boomerang, sure, because of the movie but we later learned that he's about to have a clash with Flash in the upcoming JL vs SS event, which was a link missing in New 52. Wally is already connected to Dick. And all that leaves is Vic. I don't think Johns threw that panel for nothing, he was acknowledging their bond. He could have went to any Green Lantern but Wally picked Vic instead.
2) Dick forms a friendship with Vic in JL #51. They are about same age and they bond over being the youngest around other superheroes. That's a prologue to Titans book, so this issue is important.
3) I didn't watch the movie but apparently Vic backs up Damian's TT against JL. New TT book is based on that line up so....
4) Rebirth is about restoring bonds and Vic lost many of them when he became a leaguer. Most fans complained about it and his last books failed because of it. It seems like a very obvious choice. It also gives him a relevance he desperately needed while making Titans more front as well.
5) Again, Rebirth is a good opportunity to make Cyborg relevant.
and now what REALLY convinced me....
Kilg%re.
First debuted as Wally's enemy when he first became Flash, it appears he's making a return in Cyborg's book according to solicits. Now obviously it makes sense they are retooling obscure villains to give Cyborg a rogues gallery but here's the thing: Kilg%re also appears on Titans' cover for issue 5. A month after where Kilg%re appears in Cyborg's book. Bonus points? Wally teamed up with Vic in the original story.
I really don't think it's a coincidince. Kilg%re is a very obscure villain and a very odd choice to put as a part of Wally's life in that cover.
What kind of relationship do you think Wally and Vic have in Rebirth? Any guesses?