KSail,
I went back and re-read your original post and after my little rant offer this for information.
I qualified on the 1911 in both its forms because it was then the militarys standard sidearm. It's all we had and as a squid, any time at a range was quality time because we didn't get to do it that often. Sailors generally don't carry a sidearm, nor are they required to qualify on one. I also gained Marksman on the M14 as well for no other reason than to shoot free ammuntion that had been sitting in the armory for years and years.
I learned to shoot it well and never really thought about it until I re-read your post. After I got out, the first gun I bought was a Beretta 92 or the grand daddy to the M9. I bought it because it was cool, you could load it on Monday and shoot till Tuesday with the 15 round mags and I was 22 years old! After thinking about it, it probably took me a couple thousand rounds before I could shoot the thing consistantly but, once I figured it out I could drive tacks with the friggin thing.
Your probably right, the A1 arch feels better because the muscle memory in your hand is tuned to the feel of it. It's not a hard swap and there are a bunch of folks who sell them, some with beveled mag well extensions for race guns and such.