The center of pressure travel concept was dropped years ago in favour of a fixed airfoil "pivot point" at the 25% MAC chord point and a "pitching moment" amount to describe the pitching effects that were previously covered by moving a virtual balance point which was the center of pressure concept.

This was done, near as I can make out, because the Center of Pressure concept went into the toilet for the specific lift value of CL=0 where the CP was located infinitly far behind the trailing edge. Mathematician's may not mind infinities in their equations but engineers hate them. Hence they came up with the idea of a consistent pivot point and the pitching moment which avoided the whole irritating infinity issue.

BUt all else being equal you're right. The stall angle is somewhat affected by the chord. But I do not think you can lump in acute angle delta and strongly swept planforms with constant chord wings. Strong sweep angles do generate strong leading edge vortex formations that muddy the whole stall issue to the point that you can't really compare them fairly.