Many of us who aren't hardcore competitive players had fun with SC3's combat engine. Sure, it's not perfectly balanced; but it's a long way from shitty if you're not hyper sensitive to the flaws. That's not to say I don't understand your point of view - I'm hyper sensitive to flaws in third person action games. But it doesn't make sense to call something objectively shitty and no fun if a bunch of people clearly enjoy it.
Some people play fighters just for the competition, and a versus mode is all they need. Others enjoy the mechanics of complex one-on-one fighting with AI opponents, but appreciate the formula being mixed up with SC1-stye missions, or SFA3-style World Tour modes. For all its flaws, I thought SC3's Chronicles mode was awesome. It saved what was an otherwise thoroughly disappointing game, and added a huge amount of depth and replay value because of the leveling system and the elements of battlefield strategy. I've always hated RTS games, but adding the action of Soul Calibur combat allowed me to appreciate elements of the genre in a unique context. The ability to create every character in your party and unlock new fighting styles for your team made me care much more about the fighters I was building. It was awesome.
As others have said, it's not unreasonable to want everyone to be satisfied with a game like this. Fighters can have solid combat refined for competitive play, and the game can still boast a few interesting single player modes that let non competitive players enjoy the engine.