They are "grooming" Reigns but truth is nobody knows. Not even WWE...
I mean 2025 is a lot of ages ahead. 5 years is too much, let alone 10 years. Heck, in 2005 Cena was just rising star and Batista was suppose to be somebody who becomes next face of the company. We dont even have to go that further, lets look at Wrestlemania 26 that was 5 years ago and see where they are now
Battle Royal: Yoshi Tatsu won
ShoMiz defeated Morrison and Truth- In all of that Miz happened to be "breakout star" and even he didnt come that big if you dont count that he played "third wheel" to Rock and Cena
Orton defeated Cody Rhodes and TedDiBiase- Orton is still mainevent, Cody not so much, DiBiase long gone and both are heavily hinted as "next big thing"
Swagger won MiTB- was very high in eyes of WWE, won title, lost it quickly and now is nowhere near any mainevent
HHH defeated Sheamus- Sheamus, next big thing at that time. Is somewhat big and IWC calls him "midcard Cena" but still isnt as big thing WWE wants him to be.
Mysterio beated Punk(with SES)- This is my favorite, both were big in years(Punk especially) but Punk is fired and Mysterio is questionable and probably will leave soon
Divas match- needless to say, out 10 of them in it just Layla is here now
Bret Hart defeated MrMcMahon- wasnt even a match and both were geriatrics even then
Jericho defeated Edge for WHC- Jericho is still there but on semi basis and Edge retired
Cena defeted Batista for WWE title- Batista was back last year and maybe will come back again but he is not regular(with Guardians of Galaxy as such big movie and good critics on him, he would probably be more Hollywood star and almost no WWE star) and Cena is still no1
Undertaker vs Shawn Michaels- Well, was last match for Shawn and Undertaker might have his last match this year or next and he wrestles once a year last few years
So you can see, no Bryan, Reigns, Rollins, Ambrose, Wyatt and all others that are expected to mainevent this year and have big matches. Heck, if someone was gona call in 2010 and say that Brock Lesnar will be champion again almost everyone would call him nuts.
Other then Cena and few others, most of them are gone and most people who are believed to be "next big star" are also gone or nowhere near that status. So, you cant say who will be new face in 2020(heck, even Cena might be gone before that) yet alone 2025. Heck, "Next face of WWE", "Next Cena" or all other names people are calling potential talents could be still in High School or in some development for talents. Its just too early to predict things like that in that much span of time.