The visual and audio reinforcement and cues alone are above just 'competent' to me. Something as seemingly insignificant as the design on, say, Zenyatta's abilities having the 'plus' and 'minus' on the illustration of his orbs is a sign of great visual design. The way each character has distinct footsteps is great audio design. The way it presents information to the player without cluttering up the screen is great interface design. There are countless little touches that all come together to make everything just work. Overwatch is many things and it's not a game for everyone but it's an amazingly designed game. It's telling that the year of games so far has been defined by great improvements and modernization of older games, like DOOM, Stardew Valley, and, sure, Overwatch.
The Audio seems fairly well done. The visual is definitely its highlight, though many characters are fairly basic in design so it's not an achievement. The interface not cluttering is pretty easy to do with such a basic concept of a game. They definitely did a good job with it. Can't help but not be wowed though.
Saying Overwatch and Battleborn have similar gameplay is like saying Civilization and Starcraft have similar gameplay because they both fall under the strategy umbrella. Battleborn is a fundamentally different game and is lacking the polish and solid design that Overwatch has. Not to mention the player base. Battleborn is 2016's Evolve. Battleborn is literally a first person MOBA. Overwatch is a first person team based shooter. The similarities of both games having heroes and counters doesn't put them on the same track.
I think they hide behind those labels to seem different, honestly. I could not tell the difference between them at first, other than one having minions spawn and the other being pretty much 'capture the point' over and over. It's a much more similar design than Civ and Starcraft. I'd say it's about as similar as...Dawn of War and Warcraft. Both are strategy, but Dawn of War has features that make it
technically a cross between an RTS and an RTT (unlike DoW 2, which is a full blown RTT). Neither are better than one another though, like Battleborn and Overwatch. Nothing suggests Overwatch is better other than its more vocal fans. Maybe Overwatch has more fine touches as you said, but that should also give way to Battleborn's hilarity and story.
Well I mean it's the second best game to come out this year but that's just my opinion
I can agree with it being one of the best ones.
I guess all of this discussion means I have a truly unpopular opinion
