I wouldn't count on getting upgrades as a Gold, as you did 3 years ago. I was a Premier Exec on UA for several years and agree the upgrade rate was very good. However, having been Platinum and 1K on the new UA, I can tell you my upgrade rate as a 1K is much better than at Platinum (about 60% vs. 30%).

Routes, times, etc. all matter in your upgrades, but I think generally speaking you will be disappointed if you're comparing to 3-4 years ago.

I'd suggest getting the lifetime status and test out a few new airlines.