Sorry for the quick entry without all the hyperlinks I normally put in, but I'm about to have breakfast in Hawaii and I just wanted to get this off my chest. First off, let me say that I'm a huge Lightroom fan. I use it for almost everything. I'm thrilled that Adobe has made it easier to use Lightroom with third-party software through their "plug in" architecture. I use Photomatix myself and I like the ease of integration.
But these so-called "plug ins" are not really plug ins - they're more like "export presets". You select an image (or images) in Lightroom, select "Edit In Photomatix", and then Lightroom renders TIFFs of your images and sends them to Photomatix, and then imports the resulting TIFF that Photomatix creates. I presume the newly announced Nik Silver Efex "plug in" does the same thing.
But what if you want to change something about the source image? What if you want to change the crop, or do some dust removal, etc? Then you've got to start from scratch with the plug in with your new source images.
I'd really like to have a true mechanism for adding new functionality to the develop module in Lightroom. I wonder how the layer/plugin architecture of Photoshop could be re-used to pull something like this off.