I just came across this discussion and like wow, this taught first came to my mind, when I went through some spreadsheets from Royce777 campaign and that of jurlez. The truth is, campaign managers have the right to choose whomever they want for their campaign, and we shouldn't try to dictate that. One idea I had was that it might make more sense if 50% of campaign participants were from this forum, and the remaining 50% were members from Bitcointalk. This way, there wouldn't be arguments about impartiality or bias.
Another reason why I won't argue about the manager's decision, though is that I've checked the profile history of local members who applied for signature campaigns, and many of these accounts have been inactive for months or years but suddenly became active when paid campaigns arrived. This further supports the campaign manager's decisions.
The best thing, as other members have mentioned, is for local forum members to be more active and contribute to the forum. Over time, we may attract more campaign managers from Bitcointalk who could bring in more paid campaigns.