My only real issue is line-ups. It's just a tedious scrollfest on desktop. It's the absolute worst in ST when you have 30+ position players, many of whom you want to rest after x-amount of AB, to manage. A good example of how I'm neglecting my line-up is in Mantle:
My lead-off and clean-up are fatiguing. Lead-off has a split slash line of 286/387/461 and clean-up is 309/369/614. They were replaced with 221/257/337 and 204/283/333. Normally, I'd bounce players around and have the replacements hitting at the bottom of the line-up. But "move this guy up three slots, this one down 5, this one up two, etc, etc" is just too goddam tedious. Especially when I know I'll be adjusting it again every 2-3 full cycles. So I leave the crappy hitters at 1/4 and hope they have a great game.
Does that sound like fun?