To be honest though, I can understand where the Japanese are coming from with reverse importation. Yesterday, I went on Amazon.co.jp and searched for both "けいおん" and "K-ON!" and I found that Sentai Filmwork's season 2 blu-rays are being sold for 5,280yen (part 1) and 5,853yen (part 2). Compare this with one Japanese season 2 blu-ray, which costs 6,216yen after Amazon's discounts (for a more direct comparison, Bandai's season 1's first volume blu-ray is 3,000 yen, while the Japanese volume 1 is 5,746 yen) so it's blindingly obvious why fans would reverse import.
Now, we in the west can pout and say "Japan should lower their prices!" but they obviously won't if it's working for them. The K-ON! movie costs 6,745 yen on blu-ray (£54.63) and that still sold 96,430 units in the first week on sale. Now, I think it was in a recent MangaUK podcast where it was said that the international market only amounts to 10%, meaning 90% is in Japan. Now, business-wise, how logical is it to bring down 90% to put it more to line with a 10%, when you could just increase that 10% to be more in line with the 90% or make that 10% unappealing to that 90%? Not very.
If something small like blocking people from viewing the original Japanese language track without subtitles in a country where Japan is not the commonly spoken language or region locking helps prevents reverse importing and thus allows for releases more in line with our prices, I don't see a problem with that (especially as multi-region players are more widespread). Sure it might affect a vocal minority, but frankly, how many of the casual buyers would actually care? I doubt many will. It's also a pro vs cons situation I imagine, where having the Japanese voice track without subtitles might appeal to a minority of that 10%, it would appeal to the vast majority of that 90% they are trying to stop importing.
With the American Persona 4 situation, that is unfortunate. Cutting out the original language track is perhaps taking it a step too far and yeah, it does suck that Sentai have been made to say "If you want to watch the show in Japanese, then buy the DVD instead" but as long as America and Japan share a BD region, they'll have to put up with stuff like that in the future. As it stands, Kazé have received no such request from Japan (most likely due to the differing blu-ray regions).
With Cowboy Bebop, yes it's expensive, but I'm guessing that's supposed to be a premium item even in Japan. After all, it's a HD remaster of a show that's almost 15 years old.
I don't think there's a single show I now watch on XD.