^answered your own question.

Exactly what I'd suggest. While I've never shot one, I've always felt drawn to those older A5s, though I know next to nothing about the various models/what separates a good one from a great one, etc. When the time comes, I'll be looking for an older A5 myself, and I'm ok with 2-3/4"....and hope it's a MOD barrel. However, what I see that gun being useful for (in my situation) is clays, grouse, and barn pigeons. If I had migratory birds like Geese in mind, I'd need steel shot...and I'd want a modern barrel with choke tubes for that.
While I've never shot an old A5, I have put countless rounds through my old Remington 11-48, also a recoil-operated semi. Assuming the recoil is comparable, there IS slightly less felt recoil than an 870 shooting the same load. For me, it's still an easy call=modern 870s will gobble up to 3" loads, and the 870 MAGNUM (not overly rare, in EXPRESS models) will take up to 3-1/2. I just don't think you can beat the simplicity/ease of care with the 870s. Once you've had it apart a few times, it's something you can almost do with your eyes closed.
Lastly-EXPRESS vs. "WINGMASTER". Yes, the Wingmasters are better-built/better-finished...but don't dismiss the 870 Express either. I've worked on a couple of them that were badly neglected, but I believe our family 870 Express (20ga Youth) has been around more than 10 years...and not a single hiccup. I have nicer shotguns, but it's the one most of us reach for..most.

If you were to upgrade the extractor on the Express to the same one used on the Wingmaster *cheap upgrade* you've addressed the one item with potential to fail. Granted, I've yet to see it happen in mine (x God knows how many rounds) or my nephew's 12ga (x even more rounds). I don't see it as much anymore, but there has been allot written about the finish on the Express. It's not a top-shelf, highly polished/blued finish like the Wingmaster...it's more bead blasted/satin...with an inferior bluing of some kind? In any case, treat them both well and the gun will look new for at least a decade. (mine is, and going strong).
Put either gun away wet, and expect rust.