I've considered for years putting together a 20 gauge and just never got around to it, now I've reached the point where I just don't understand the desire.
1. There is no extra credit for hunting with a 20, it's not like a recurve killed deer versus a rifle.
2. My 12 isn't that heavy to tote, and I like the extra weight for fitness reasons.
3. If I miss or potentially wound a bird due to a sub gauge and misjudging yards or just because I'd be furious I didn't have the 12.
4. I shoot TSS out of my 12, a 3.5" 2 1/2 oz load so killing power is exponentially more than a 20 one would think
5. Recoil is unnoticed on a 12
Those are just a few of the random thoughts I have rattling around. No judgement to those who do shoot smaller gauges, I just fail to see the point.