[@Rune_Alchemist] It appeals to me because:

A). It looks awesome in general.

2). As a Team Fortress 2 Fan, it also caught my interest due to that its looks like a futuristic and expanded version of TF2 in a way here and there. Some characters I can actually relate to when coming from TF2 like:

Scout = Tracer
Soldier = Pharah 
Pyro = Mei
Demoman = Junkrat
Heavy = Zayra
Enginer = Torbjorn (Or Symmetra)
Medic = Mercy
Sniper = Widowmaker
Spy = Reaper
(Btw, I'm doing an art project on this crossover too lol)

But not only do they have these similar characters, but a whole new cast of em too, meaning you can experiment with new concepts and the like. So overall, it's just exciting and even kinda new too. So if you played and like TF2, your gonna LOVE Overwatch!