You're brutal Most people that shoot DA/SA and train with it are actually very good shooters because they of all people understand the value of trigger control. If this gentleman wants advice on how to become proficient on a platform, I deon't think we should discourage him by telling him (in Yoda voice) MMMMM, too old, too old to begin the training, are you
I've been carrying DA/SA Sigs for over ten years by employer mandate and can shoot them fairly well. (sub 5.5 FAST, high Intermediate (106) at Rogers, 2nd place at this year's RM Tactical Conference) With that said, if I could transition to something else with a reasonable, consistent trigger pull, I would in a heartbeat.
It isn't that the platform can't be shot well, it's that it requires extra work. People I respect, say that shooting the DA/SA well required 20-25% more effort than a Glock, M&P, 1911, etc. In a world of finite resources, there isn't much reason to spend those resources working extra hard when you could be a better shot with a different platform.
You wouldn't see any improvement simply by making that switch. At your level of performance, the DA/SA isn't making any difference. If you switched to Glock tomorrow and put 10,000 rounds of dedicated practice into the switch over two months would you be better? Sure. If you took that same 10,000 rounds and put it through your SIG in two months, would you be better? Also yes.
What you will see if you switch to a SFA or SAO gun, though, is that pretty soon you'll find shooting a DA/SA gun less easy than it used to be. Ask me how I know. I can still pick up a SIG or Beretta and shoot it ok, but now the DA trigger that used to be literally unnoticed is something that requires conscious attention. That's a ding on me, 100%, and not the gun.
I'd switch back to a SIG DA/SA with short reset mechanism in a heartbeat if I had confidence in the gun's reliability and durability. That's just an amazingly shootable trigger.