Personally, I think any of the apps that go landscape are fine. The rest do not need to be... Do you really need apps such as the Phone app in landscape? I think that when Devs are developing, it is their decision to incorporate the ability to go landscape... It's not Apple's call...
However, they control incoming app requests, and they control on how their default apps work...
As well, I think the iPad has a large enough screen, which iOS can take advantage of and use more landscape apps... It just looks more nicer on the iPad than iPhone. I know you have that picture of your apps turning landscape, but I don't think its practical, especially for most users.
Don't try to fix something that is not broken. If it seems broken, fix it yourself. You obviously did by jailbreaking and tweaking...