You should not get high expectatives of something just because its shiny, that thing you linked looks like a bad done Castle Crashers in unreal engine, the kind of game that bores you after half an hour of play.
Neither games are sub based so... you can just play them both? I wouldn't quit diablo over it though, just because a game is nice to look at doesn't mean it's actually fun to play either. I'll probably check it out though.
Some people have strange needs to tell others what game they want to play and that game is better than what others play. I'm sure OP does this at the official forums as well. If this is Korean it's gonna be F2P P2W shit, so meh. Also, robots are meh.
Nice graphics, but I don't care for the over-sized weapons and armor, same reason I don't play WoW. What most people don't get when they come here with a new game they think is better is it's not entirely about the graphics with Diablo. The story line, the characters which span nearly 20 years, the comedic injection in dialog with the towns people and NPC's, the feel of the game, along with the graphics all make up what we like about Diablo. If you are just about graphics and physics, D3 is good, no question D4 will be even better.
Fixed the link for you. It should work for everyone now.
While I'm not a big fan of your tone (I find it somewhat trollish, only meant to provoke others) on saying D3 is dead, I'll leave this be so that people can discuss and compare the games' features.
I really liked the graphics, they seemed very fitting for a 2014 game. The gameplay looks fluid enough, but I don't know how it would work in an mmorpg environment (big parties? or limited to 5-10 players?). I absolutely lovethe traps, because I think they're a staple of the dungeon crawling genre and an area that D3 is severely lacking for no reason at all.
All in all, definitely a trailer that got me very curious, and I think that's the most important for any game trailer. I'm somewhat skeptic on game developers' capacity of delivering just rock solid gameplay these days - there's too much garbage "ERMAGHERD LOOK AT THIS, IMAGINE THAT" features, and very little consistency and gameplay quality, and maybe that's why Blizz games are so succesful, they usually nail that.