I will admit that Blender has an unusual UI that will deter a lot of people.
Like I said before it's good to see some actual competition in this space.
I find it interesting that it seems that for a some people, Blender is their first experience with a node-based editor. They've been around for years. While I haven't used Nuke (or Shake), I was very good with Houdini for CG which is all based around nodes. It does include some basic compositing (or at least it did the last time I used it).
The other big node-based thing is audio synthesis / effects, for example Pure Data. As far as I know these are the only areas where dataflow programming has really taken off.
Matlab's Simulink is also node-based (probably because of LabView). It's also widely used.
Overall Blender, Kdenlive, Natron, and perhaps the new Openshot 2 are the current best FLO options for video with some stuff like Pitivi something to keep a watch on.
I'm not a professional video editor of course and everyone looks at this stuff with different slightly desires. Blender had NLE before kdenlive even existed, if I recall correctly. My comment was in reference to that period of time. It's nice to see competitors like kdenlive and natron have appeared.
What must-have features are missing? Last I checked it did basic video editing really well and it's compositing engine is really quite nice. It's not Adobe Premiere but for most use cases I've found it to be the most complete and featureful editor out there that is both multiplatform and Open Source.