This is just my two cents, but here goes:
Despite never really participating in an entire WAR, I will be the first to admit that my feelings are a bit shaded by the rose-tinted glasses of nostalgia, but if a change is necessary going forward, than a change is what needs to be done.

I think that most of the logistical issues up for debate look fine to me, but, I would be interested in being a gym trainer and, for what it's worth, I'm going to echo the concern with requiring gym trainers to be willing to compete in four sections, although I will concede that I might be able to pull it off somewhat in a pinch if the sections are the same as last summer's WAR. I see no issue with the requirement of four sections for gym leaders however, that's why they get the titles after all.

In the other thread, you mentioned that this format would likely mean no Team RP, which makes me a little worried, not just about the scrapping of one tradition that I have always looked upon fondly upon (especially the example from one year's winter parody WAR), but also about how the RP section (or equivalent) for this league would be, i.e. would it be limited to RP creation or would there be some way for those with a greater interest in RPing over GMing to participate in a more comfortable environment. While I believe that creating a successful RP requires some level of understanding of your audience and possibly some collaboration and brainstorming with others, it still strikes me as a lonely solitary work that fails to account for the people-to-people interactions and reactions that firmly separate RPing from writing fanfiction or other written works where the amount of group input is limited.

This actually brings me to my biggest concern with this model, that being not necessarily the lack of teams, but the lack of the community that the WAR and those teams represented, even if the practice did not exactly line up with the theory. While I think that this is definitely an innovative model and will address some of the weaknesses of the WAR model, i.e. I am willing to concede that smaller and perhaps more focused gyms could possibly strengthen the bonds within the team, I feel that the idea of gym challengers is very individualistic, replacing interactions between teams with interactions between singular challengers and gyms, or, I fear, between challengers and gym trainers without any sense of real continuity between the pursuit of a badge. One idea that might help with that, if someone smarter than I could figure out the logistics of it, would be the optional organization into squads, similar to the traveling groups on the Pokemon cartoon or the ninja squads in Naruto, where each member complements the others on the squad? (That's one idea I have for combating this potential pitfall, but I think that there is a better one at the end of this post.)

Anyway, I feel that reducing the essence of the competition to a series of one-on-one match-ups in different categories, albeit with a panel of judges or an ASB or URPG ref, really limits the community aspect of this idea and therefore the nature of this being a special event. If this was to be a continuing feature on PXR beyond just a summer festival, I would be all in favor of the finished idea being implemented, but I would like to see something that offers more large-scale simultaneous participation at least accompany it to make up for the shortcomings that I personally believe are in the proposal.

Hence, my one idea that might actually contribute to the discussion: I think that it would be possible to construct a kind of Team (Gym?) RP, or even general event, story line that would allow for a greater interaction between "Gyms", giving a further incentive for people to join Gyms and to act as a gym and not merely a loose collective of individuals sharing a banner. I would be more than willing to offer up my meager skills in whatever service that goal requires as well.

tl;dr:
- I'm a little hesitant about number of categories required for gym trainers, but seems manageable personally.
- No Team RP makes me sad.
- Challengers and challenge model seem less community-minded and more isolated, so I think there should be a complementary event to address that.
- Maybe some kind of "Gym RP" (or other event) could fill that role?