#1: I never noticed this. I created a project with a white background and I see what you are talking about. The text isn’t clipping the drop shadow. That’s a drag. Another workaround would be to do your text in Photoshop and clip the drop shadow. I’d call this a bug that needs fixing.
#2 This is only with the timeline, and I agree. CMND ARROW should move the object selected on the stage.
#3 How much memory will AE grab? Only 2 gigs. What happens when you fill that up? It swaps to the hard drive. At least Motion utilizes up to 8 gigs (minus System). Anyway, go to your Motion preferences and play with the Memory/Cache preference. Set it to 70% and I think you will have less HD swapping.
#4 I did exactly what you said and my key frames moved with my duplicated text. In any case, (#5) OPTION click on a key frame and they all get selected. I agree that we should be able to drag-select key frames with the cursor in the timeline.
I think you are getting frustrated because you are so familiar with AE and you are learning how to do things in a different way. There are obviously some things that need fixing in Motion (there are still things that need fixing in AE too, BTW). Motion is less than two years old.
You will get more help on this forum if you be less sarcastic. The whole AE versus Motion thing only creates flames. We could talk about what a pain it is to do basic things in AE that will make the drop shadow bug in Motion seem pretty minor, IMHO.