I think not, the downloader is strictly only for downloads and notifications and many people do not like your idea.
That's one of the totally awesome things about optional functionality. It allows people who like it or even demand it before they'll fork over money to be able to have the functionality they'd like such as this, however at the same time - the people who do not like it - don't have to use it! Awesome! Both groups of people can get what they want!
Granted, some sort of launcher may be neat, but if you buy (digital) games from different sources and whoops you have half a dozen mandatory launcher/clients gobbling up resources on your computer. Personally I don't really like the official GOG downloader and I'm using the web interface (more reliable) for downloads, but this is due technical reasons. I'm glad having choices on downloading games here on GOG.com.
I totally agree with you on that, choice is good and I very much appreciate the options we have now and also hope for more and better options in the future (better being subjective of course).
On my previous computer I had GOG Downloader, Steam, Desura all set to *NOT* start up when the OS starts up because they each used a significant amount of RAM and CPU resources just sitting there doing nothing on my aging piece of junk computer and I needed every byte of RAM and every CPU cycle just to have a lot of games and other software be even remotely bearable. I am sure many others are in the same boat. The cool thing about GOG Downloader is that you don't even need to use it at all if you don't want to, and if you do want to - you don't have to leave it running all the time or during OS startup but it's optional either way so everyone can have it how they prefer. Nowadays my preferences have changed since I built a brand new PC fully loaded and I'm no longer resource starved. Now I prefer the convenience of having these things run all of the time ready to be used and monitoring for game updates and whatnot. They might waste some resources but I've got 32GB of RAM and 8 cores @ 4GHz so having GOG, Steam, Desura, Origin, Uplay, and Capsule all in the background at once uses probably 0.05% system resources and it's more effort for me to disable them than to care. Hehehe. I have all but Uplay/Origin/Capsule set to load at startup (because the latter 3 I rarely ever use).
AFAIK the GOG Downloader uses a custom download method with checksummed chunks for all stuff. The size of the chunks are not as fine-grained as rsync's, but optimized for paralell downloading and saturating the available bandwith.
Ah, that makes sense. Hopefully they can come up with a new update mechanism that works well with new games that get frequent updates without using lots of network bandwidth etc. for people who would like such, while simultaneously continuing to give the experience that people currently like as well. Totally doable, they just need to pour some more coding hamsters in the wheel and churn churn churn some new bits. :P