Looking for feedback about changing Brendan/May in a game

Hello everyone! Despite the name I may have stolen from my best friend(sucker ^^), I am Sudtrap.
I am working with a small team on a fangame that is a pseudosequel to ruby/sapphire, that takes place in Kanto. Having heavily compared the two scripts between the characters, we found... (drumroll) a whopping (approximately) 15-20% difference between their dialogue. Many times, Brendan would say something was awesome, and May would say it was cool or something.

We feel that the Brendan and May would be more interesting if they had more distinct personalities, and are considering potentially changing their personalities a little bit.

Basic changes being - Brendan as more of a sciencey nerdy kind of person
May as more of an outdoorsy genki girl.

What's your take on the characters?

Do you think this is a good idea?

Also, how do you feel about aging them a couple of years older between the games? (perhaps in the mid to late teen category as opposed to young teens?).

I'd love to hear from as many people as possible about this, so we can make the best decision.

Thanks for your time!
Sudtrap from Team Grendelsay

I don't have any personal headcanons about Brendan or May, but I am fine seeing other people do more with their characters. It's far better to have a character with some interests (science, nature, etc.) than to just have generic supportive rival who just says everything is "cool/awesome." Giving Brendan and May more of a personality would also add to the story, because it makes them into actual characters instead of just spouting generic dialogue.

The aging of them makes sense, especially if there is a time span of a few years between the games.

Thank you so much for your feedback! I'm glad you feel the same way we do about it.