*Long Answer: *I agree that BOSH can be better, as can all software ;-).
However, the certification process for offerings isn't about
experimentation in the ecosystem. It's about consistency across the
distributions. Requiring BOSH as the deployment method gives us two key
things: (1) much more consistency for operators of the platform and (2) a
consistent target (really a least common denominator) for ISV's packaging
software for backing services. The value of consistency year over year
doesn't diminish the value of experimentation outside of the certified
distributions.

The consistent target from an Engineering perspective should always be the
contract or interface, but should never degrade to the point of being a
particular implementation. This has been damaging in many open source projects.
Where competition has always fostered excellence in these projects. Look
at gcc and clang, or vim and neovim where the original projects were in
states of decay, but a competitor emerging kicked them back into gear. Settling
on BOSH as a lowest common denominator will make BOSH stagnate.

With only one deployment mechanism and no clean interface to separate Cloud
Foundry components and releases from BOSH implementation details, it's possible
that the lines become so blurred that BOSH becomes impossible to remove. Even
if at some point it becomes desirable because the community has reason to move
away from BOSH (ie. rewrite time, or perhaps a better mechanism has been
discovered or even leveraging a new open source project to do the same) it will
be harder to do so, and hamper the evolution of the project.

I'd propose keeping BOSH out of the CF certification, and instead start work
on describing the BOSH <-> CF interface more cleanly, and work to improve that
so that various deployment mechanisms can be used all the while retaining the
consistency which seems to be the real goal we're trying to strive for here.