I actually do prefer the old AC system. Thac0 can be tricky but we used to chart it out on the sheet as players. As a GM it it’s easy once you get used to doing the math (I would say 3E was just as hard, if not harder because you often had to add large numbers in your head on the fly, whereas in 2E the numbers were fairly contained). I don’t see us going back to it for the current editions but some of this stuff feels less wonky than it sounds or than how it is often remembered (I expected Thac0 to be very tricky when I went back to it, and at first it was initially but that passed pretty quickly (especially when I realized at times it was easier than some 3E math)