Everyone agrees it is bad but I guess it is up to you to decide how bad it is.
If i am being honest, I found Elektra and Ang Lee's Hulk much more boring, I'd probably say those are worst. Those films were better structured but it's pretty much the same, especially the Hulks third act, it made no sense. Hulk did have much, much more action so more might rank it higher but I do think that ending was worst.
I think this film is easy to fix and make good/decent though, the first half isn't bad, it isn't great but the acting is good and origin is slow but tolerable and interesting enough. They should have left Doom out of it, maybe mention him as an easter egg but not be there with a huge presence, make Annihilus the villain from the planet they found and then the third act would have made much more sense. Add a few good action scenes, add structure and this film would probably be at least borderline fresh on RT.