The PP thread in the Chase forum has ~1000 posts in 16 months. The PP thread in the Citi forum has ~300 in 4 months. So I think the post volume is sufficient for a new forum.
I see two potential big positives that might result:
1. Having all PP info in one place.
2. Encouraging separate threads for separate topics. Now, all PP posts in each of the credit card forums are intermixed into a single thread, and searching within a thread is much more cumbersome than searching for threads within a forum.
But I also have some reservations.
a. You would want some active moderation, at least at first, to encourage users of the credit card forums to use the new forum for PP posts.
b. Even then, there's ambiguity about access questions. "How many guests can I bring to PP lounge with XYZ credit card?", would that best fit in the PP forum, or the CC forum? What about "If I cancel my XYZ bank CC, how long can I still use the PP card?"
c. For questions about the lounges themselves, they would still naturally fit in both the PP forum and the airline's forum. Yes, a majority of FT'ers using the TK lounge at IAD are likely using PP to get in. But if someone flying TK J class has a question about the wine selection in that lounge, should they really be asked to post in the PP forum and not the TK forum? And if not, then we haven't necessarily solved the info-spread-across-different forums challenge.
I'm interested what others think.