Well I am under the impression that it is 4 CAMPAIGN DLC as opposed to anything else as that is what is stated so hopefully it is actually fleshed out stuff. It has also been confirmed that Fiona will be probably lead character in at least one of the 4 DLC.
As for what I would like to see, aside from the huge notepad of suggestions I have been working on, I generally compare games like this to Rachet & Clank from the good old days. In that case I would have loved to have seen an Arctic planet, a greener metropolis, maybe an ocean planet, a space station. Customisable ship (Sanctuary’s exterior), better room customisation.
Obviously Ultimate Vault Hunter Mode, increased Character levels, possibly upto level 70. New higher class of weapons & gear and probably lots of other stuff that will never be added too.