No need to be lonely.  You can (and should) have community projects on dub.  The dub repository is a distribution mechanism, if you want community contribution to a library advertise as such and git er done.  With git.  Until done.

If it's worth inclusion in phobos, it will rise to the top.

Moving things towards phobos won't help with fragmentation, will just piss those off who disagree.  Better path is to put solutions in dub for people to use and abuse, see if one becomes dominant.  Only then look at moving to phobos. 

Proper package is what works to get a particular job done.  Doesn't matter if it's in phobos or dub or what, as long as it does what is needed.  Competing packages will either sort themselves out (given right community involvement) or show there are multiple useful ways of doing things.

See the java ecosystem for examples, there are plenty of things that are third-party but considered 'standard' more than what's in the standard library (joda time, slf4j, etc).  Personally I'd prefer a small standard library with lots of high-quality libraries to pull in as needed - it's suboptimal when the best solution is not what's in the standard lib.

I like the idea of having a 'recommended' section in dub, for those things considered by the community to be good.  I don't think anything should even think about phobos inclusion (even on-path-to-inclusion) until it has been used and abused enough.  We have this nice package system for non-phobos stuff, should leverage it.