People should move to use `opam` files rather than `_oasis` files to keep their metadata. For one thing if you put it at the root directory of your distribution it provides you first class support for `pin`ing packages which is bloody useful for testing fixes and making preleases. 

Frankly the `_oasis` way of doing things seems a technical dead-end to me, all these useless and slow layers of indirection, generating files you semi-understand and that people commit to their repos results in a rather ugly overall picture. It had its use at certain point, but now that opam is firmly in the equation and given the way it works, having a meta system to generate generate build systems (well I think it still only supports ocamlbuild) you don't understand seems a moot point to me. It's a piece of bureaucracy I find hard to see any value in it.