Here's the issue: All alkaline cells leak given enough time. In my anecdotal experience however, these brands leak at noticably different rates.
I haven't noticed much in terms of differential rates of failure. As you say, long-sitting and little-used alkaline cells all seem to leak. I can't recall ever having had an alkaline cell sit in a flashlight with, say, only a couple uses across a year where it didn't corrode and leak. Irrespective of brand.
I suppose there would be some variation, from brand to brand. Though I've yet to see it.
Of course, for the past decade and more, I've strictly used waterproofed flashlight bodies (w/ o-rings and good thread sealant). So even had I still been using alkalines I suppose I would be experiencing less of that "traditional" leakage problem alkalines seem to have.
Much happier, from a leak standpoint, now that I'm with Li-Ions exclusively. Of course, there's the unquenchable explosion and fire problem, but still.
Another day, different problem, I guess.