HTTP/2 -- what's going on?

I plan to code a mighty web server. But I am unsure: should I do it in HTTP/1.x, or HTTP/2? I really don't like doing it in both (I know HTTP/2 is backward compatible to HTTP/1.x, but if it's superior AND is going to be adopted by the majority then I will only do it in HTTP/2 without the backward compatibility aspect).

How is the future looking like for HTTP/2? Are there any hints from standard bodies to change HTTP/2 or undo their mistakes?

Is HTTP/2 really worth it?

Finally, how is the expected HTTP/2 adoption by web browsers?