The best current official source for information on the future of the Developer Console would be Nathan Totten (@ntotten).
The last official thing I saw was in The Future of Salesforce IDEs blog post.
I don’t have a roadmap to share today, but I do want to assure you that this is an area we care deeply about and are investing in.
DISCLAIMER / SAFE HARBOR / FORWARD LOOKING STATEMENT / LEGALESE
The following does not constitute something official from Salesforce yet, so don't come back to me if somehow the developer console is still the only fully integrated web-based IDE for Salesforce in 10 years.
Unofficially, you can turn to twitter:
@ntotten @ccoenraets Any plans to add to the DevConsole support for #LWC? I checked in Spring19 org and I needed to use VScode to create them. Thanks!
Unfortunately, DevConsole will not get LWC. Building a modern dev experience for LWC is simply not possible in DevConsole. However, we are working on a replacement tool that supports LWC (and everything else) that will be much nicer. Details coming later this year.
Another good one:
Don't forget to let us know what you want to see in the next version of "Dev Console" by opening feature requests on Github: https://github.com/forcedotcom/devconsole/issues/new?template=feature_request.md …
Tooling API info will be documented soon (I think they are releasing all that on the 17th). Regarding DevConsole, we will NOT be supporting LWC in DevConsole. We are currently working on a replacement to DevConsole that will fully support LWC (and existing metadata/code).
The one thing I can say from that...
Visit https://github.com/forcedotcom/web-tools/issues and register what you would want to see in a future version of the Dev Console.