So after reading most things (I didn't read everything) here's my thoughts.
I think overall the keynote was good and positive. It had a lot of great innovation and ideas. I think on the whole MS is moving in the right direction and it would appear their 'software' focus is the right idea.
Saying that I have some other points.
Though making it easier to get developers on to W10 doesn't mean it will happen. Since I'm not a developer I have no idea how easy it really is so I can't say one way or the other if these innovations have any ability to attract developers the way they hope. I can see more Android devs rather than Apple ones coming over if I were to choose. I've found some Apple devs to be a bit snobbish about developing for other platforms. It's really unfortunate these types of tools weren't around when WP8 first came out. I think it would have made a big difference. I'll give credit here to Nadyala for that thinking.
Continuum. Great idea. It's sort of like a geek dream from years past come true. I remember when phones started to get 'smarter' and the desire to have a full fledged 'pocket' computer was around. My main concern here is the markets that MS is big in might be ignored and that's a concern. When your largest markets are emerging having premium handsets as the only means of using Continuum might make it niche. To me for this to succeed and become the norm use it needs to have universal appeal. I think having a multilevel approach here will make this possible. Sort like the different levels of CPUs that already exist. Certain phones will be better with certain apps. One key thing is that they would be able to run full Office regardless. Think about that in context. Emerging markets having access to full Office on a cheap phone. That would be a selling point right there. I guess we'll see.
The new browser I'm neither here nor there about. I think some of the new integration ideas sound great.
Same goes for the new Office stuff.
I'm neither here nor there about the Linux/Mac stuff. I guess it's good.
Lastly, HoloLens. Again. Great idea. For me? Probably not. I can see the benefits of it though without doubt.