Brighter projectors being more prone to artifacting is a known fact, not unique to one setup.Which ALR screens have you used with which projectors out of interest? Would be interesting to hear brands of screens and projectors where you found issues and if so which throw ratios? Could guide us all on what circumstances do and don't work.
In my experience the exact opposite is true, re: hotspotting relavant to brightness of PJ
Using HW40ES on an ALR - Hot spotting, specifically centre of image brighter than edges.
Using Epson 9400 on an ALR = Couldn't perceive any hot spotting
Using Draper React screen.
I don't know if the Epson was actually brighter. Depends on the lamp mode, preset, lamp hours.
Brightness uniformity is one aspect that can affect it, but they are both the same.
To asses hotspot a white background should be used.