I don't really know what people expected of Weiland. I've never owned an STP album, although I've liked a lot of their hits, they are catchy and he's a charismatic guy. But he's not the type of vocalist that you listen to over and over again. He's just not.
Speak for yourself...
Ive been listening to nothing but STP for the past 2 weeks, and the bands best moments are trascendent - as good as GNRs best, in my opinion. That includes Scotts vocals. His melodies in "Lady Picture Show," for example, are downright beautiful. Another non-STP track with amazing melodies is The Magnificent Bastards' "Mockingbird Girl," especially the end. Theres more, but Ive praised Scott on this subject in plenty of other threads, so Ill spare you.
But if you dont dig Weiland, thats cool. Im not qualified to give an opinion on his performance on this particular album (Ive liked everything Ive heard so far...), but I would only suggest you check out more of his material before writing him off like that, because theres plenty of people that listen to him "over and over" again.