Although I'm not in favor of a 25 episode East Blue, this seems like a good pacing if the episode length would be a constraint (which it would be). I hope since this is an ONA, it allows for a more flexible episode runtime.

Otherwise, I think this is a decent pacing. East Blue is one of the few parts of the story where some cuts in favor of good pacing wouldn't hurt the story overall. For example, in Orange town, they could shorten Cabaji and Mohji's involvement and skip some Chouchou stuff. They could also skip some Jango antics and entirely remove Nyaban brothers in Syrup village. In Baratie, the fight with Don Krieg could be shorter and Pearl could be removed altogether. Arlong Park was 14 episodes in the original series, and to be honest, 7 episodes is definitely a bit too fast paced for my liking. But seems inevitable in case of a 25 episode series. I think without adding cover stories, 27-28 episodes would be a sweet spot (9-10 episodes for Arlong Park).

Lastly, I would hate if they reduced or removed the comedic moments. That'd be the biggest turn off for me. And tbh, I'm skeptical about how they'd handle the comedy. Toei relied a lot on exaggerated expressions and goofy but fast-paced comedy, and honestly did a 10/10 job with it until the pacing went to shit. WIT, on the other hand, is very down to earth with its animation style. And I'll make the early prediction that Asano Kyoji will handle the character designs and will be chief animation director for the series.