Sounds alot like Kouta from Gaim, if you ask me. Not that I'd complain, his story arc is one of my favorites in Kamen Rider, and Gaim is my favorite series. I think the only way they could really stray from the past completely would be to make the character a bit of an anti-hero at the start, which i doubt will happen because Kamen Rider from a cultural perspective is largely about showing kids how to take on more heroic, or upstanding traits, and people might feel that if the character was a little bad, rather than just a little unprepared or immature at the start, they might be a bad example for kids. But i think its an important lesson to learn that even someone who has done bad things, not just mistakes, but willfully bad decisions with full knowledge of the consequences, can find a sense of justice and virtue under the right circumstances.
There are a few ways other than that, that are less subversive, and thusly more likely, that could be big changes too though. They could go for an older character, less of a young adult finding themself, and more of an older adult who feels secure in their identity and what they do as a Kamen rider already, but comes across something new that changes the way they look at things. Sort of like Garo, I guess.
But If we get another young guy, i think we'll probably see a repeat of one of the types of characters we've seen before, and judging by recent trends it'll probably be a lovable goof-ball, who's just learning his new powers, and trying to juggle that with his job/school/family-life. No hate from me, i love it, but it would be nice to be surprised again like I was with Gaim.