Yes I've tried that. It shortens the RSNS leads but makes many other things worse. As your Mosfet gate drive signals getting longer and will be routed under the inductor and switching node, also the feedback trace will have to be routed directly on the bottom layer from VOUT to the regulator on top. And that feedback trace I consider much more sensitive than the RSNS traces.
Sounds like you've thought about it carefully, and I wouldn't argue with you. Your argument is valid, and it would take a quantitative analysis to determine which is the better approach.
Based on my own experience I would, nevertheless, still put RSNS nearer to the controller, even if that means the feedback trace is longer.
The reason is that the voltage across RSNS governs the cycle-to-cycle switching points, so any noise on it will translate directly into jitter in the duty cycle of your regulator. This can add noise, both electrical and acoustic, and can make the regulator unstable under certain circumstances. Although it's low impedance at dc, the layout you have adds quite a bit of series inductance.
Noise on the feedback line does, in my experience, tend to be less of a problem. It's setting the dc operating point of the circuit, and the compensation network means the circuit responds to changes on it over a much longer time scale. In other words, its bandwidth is lower, and impulsive noise on it has a correspondingly smaller effect.