Wrong, freesync can now be enabled on all 10XX and 20XX cards, enable freesync on your monitor and you should see it identified as a G-Sync monitor in nVidia Control Panel. As for your question, I recommend 144hz for any hero regardless, you literally see more information on your screen.
Won’t really make a difference for Mercy. May help with hitscans if you’re duelling Tracer/Genji, but not much else.
Visually the difference between 144 and 60hz is about as big as going from 40 to 60, but the actual difference in your gameplay won’t be that big.
Would still recommend it for everything anyway, because it looks much nicer.
IMO you don’t need it for heroes like these that don’t require much aim, 144hz are a must for DPS and some tank players.
Think that i even play with an LG Flatron F900P (19" 4:3 CRT monitor, i hope to pick a 21" Sun GDM-5410) at 140hz with a stretched 720p
I dont see problem there, because my Picture is still when Im using pistol. It´s starting to be worse, when I will start looking for my teammates and checking whole situation on the battlefield. When Im turning camera too fast it´s not smooth yet. Maybe its tearing, because of that non-synergy between graphic card and monitor. I will try change it and see if that was problem.