Some thoughts on a few of your very interesting and educational comments:
m. 2–3: If these are indeed accent marks rather than diminuendos, I would argue that they are better placed inside the slurs. This is particularly true if they are not to be angled, because, as you point out, the slurs forces the engraver to angle them in order to retain the ideal balance of white space.
This also makes me question whether or not the length of these markings is correctly perceived in the engraving. Shouldn't such intensity marks be a lot shorter in order not to be confused with regular hairpins?
m. 5: Disregarding the need for adherence to Brahms intentions, do you as a pianist really prefer this notation? To me, the original version of m. 5 seems a lot simpler and cleaner, and I would think that any redistribution of notes would be completely self explanatory to any reasonably competent musician.
m. 16: I agree with your objection to the rest placement, but I'm not clear on whether you prefer there to be a single rest or not. Two rests in this situation seems unnecessary, even if it is in accordance with the general practice of the piece.
m. 17: Such a natural seems a bit unnecessary, since the A in this octave isn't altered in the previous measure. Including it will visually obstruct the short ties from both directions, and might therefore be better left as is.
m. 45: YOU CAN DO IT!
