And Transformers 2 is a different beast entirely, since the IMAX cut actually featured differences in footage (extended fight sequences, I believe), while The Dark Knight's 35mm and IMAX cuts are exactly the same with the exception of aspect ratio.

transformers 2 IMAX sequences are presented in exactly the same way as TDK is. The fact that there is also 30 seconds of additional footage have nothing to do with it.

And no, I don't think creating a version for 4:3 TVs is pointless, especially if you want to recreate the IMAX experience of a shift from 2.39:1 to 1.44:1 as closely as possible.

If someone wants to watch non-anamorphic movie on 4:3 TV or even anamorphic on 16x9 TV with black bars on both sides during IMAX sequences, yes, in that case it makes sense.

My point is, it could easily be done, but whether it needs to be or not is up for debate.

That is right.

I think that BR version handles aspect ratio switch the best possible way for home viewing.