Well, I suppose a larger pool of players has it's pros and cons for the PBE. On one hand you have got the over 9000 queue, the trolls, AFKs, and the possible erosion of what was once a much smaller community of testers. Perhaps it is something like the endless September.
On the other hand, more players does provide Riot with more feedback about the content as well as a diverse array of systems for exposing technical issues. Riot, please correct if I am wrong about this.
I have to wonder if there is a middle ground to be had. There doesn't seem to be a currently obvious hotfix for these conundrums, so perhaps what is needed is time for the community to readjust to the influx of players. Eventually the trolls and the like will either be banned or mature.
Personally I don't mind the queue being over 9000, I think it's a funny reference, and I don't really mind being patient. So maybe the queue time is hardly the most pressing of concerns regarding Riot's testing platform. There is the live server as well after all.