I don't think most people who are tech-savvy or are at least half-informed disagrees with you that the white MB is a better system performance-wise when compared to the 13" MacBoor Air and is a much less expensive option when compared to the 13" MacBook Pro, regarding dollar value for features. And I also completely agree with you that the current 13" MBP is
"an over-glorified non-Pro MacBook", but the reality is a lot of people are buying these 13" MBP's, and it's partly due to it's stylish form factor in contrast to the dated looking white plastic 13" MB. And I'm willing to bet more non-Pro users buy this system than otherwise.
So, this is where I think Apple will address the current "choice bottleneck" for consumers that is going on currently between the 13" MBA, 13" MB and 13" MBP and will simplify the lineup a bit more by potentially dropping one of these products. If the white MB remains for this next refresh then I'm pretty sure this will be it's last generation before being EOL'ed.
For this upcoming refresh I can see Apple offering a 11" & 13" MBA and 15" & 17" MBP as their primary laptop focus, with a "legacy" 13" MB/MBP as an option for those who need a system between the MBA & MBP for both price-point and system feature considerations. That's just a guess, but we'll all know soon enough, won't we?