Oddly, that picture comes from tesnexus.
Hypocrite much? http://oblivion.wikia.com/wiki/Blackwood
Ok, now tell me exactly what is so swampish about that picture? The fog can happen anywhere, so we'll rule that out. The person taking that picture has just took it during a foggy day. I mean, just look at the bottom two pictures. There are no dramatic changes in any of the detail (flora, rocks), there's only the slight retexture, and occasional slightly different mesh. If you look at Morrowind, for example, the trees are vastly different between the Bitter Coast (an atual swamp), and the Ascadian Isles (An actual forest like region, we'll ignore the mushrooms).
Can you not honestly accept that Oblivion has flaws? Every game, Oblivion, Morrowind, Daggerfall, Arena, Battlespire, Redguard, TES Travels, even Super Mario 64, all have flaws. Every game. Oblivion is no exception. The bland wilderness is one of those flaws.
Also, there's a Morrowind section of TesNexus. It's just mostly Oblivion.
Look at http://www.uesp.net/wiki/Morrowind:Bitter_Coast. Not taking the outdated graphics into acount, that swamp actually feels more of a swamp than blackwood. There's scum filled ponds, and just look at the shape of the trees. There's moss and vines hanging off some.
I won't reply for some time. My internet is going crazy. Took me 20 minutes just to load this page.