Wow, I had a lot of these same thoughts recently re. tumblr and DW, and actually just posted my first entry in ages here (due to having something I felt like writing about but didn' t feel comfortable posting in public, even pseudonymously). Tumblr does have its good points...I kind of like the way it makes me feel like I can just post whatever (even just a picture) and not have to worry about editing or keeping up any sort of long-form language ability when I want to communicate but can't write in a "bloggable" manner. But it's definitely a very different arena than the DW/LJ-type sites and I am glad you lot plan on continuing to use DW a bit, at least.