F-5 to Vince, for me, means Triple H vs Brock Lesnar at Wrestlemania. Now I think that if CM Punk does not win the WWE Championship at EC, he will wrestle The Undertaker at Wrestlemania. Then John Cena will face The Rock(c) at Mania for the WWE Championship.
I don't think WWE should put Ryback vs Lesnar for the moment as he is booked and has unfinished business with The Shield. If Lesnar really sign a 2 years contract, then WWE have time to put Ryback vs Lesnar, and that would for sure be huge for Ryback's career.
I hope this time, Brock Lesnar is here almost full time for 2 years, so he could do better than before.