You are perfectly within your rights to fork the package off to your own copy and do whatever you want with it. You are welcome to fork all of hackage if you need to.
People can then choose to prefer your more proactive maintenance strategy or that of the original packages.
The concern I have is over the notion of coopting maintainership of the original package on such a short timeline. I personally find that to be the alarming part of this whole discussion.
I hereby formally do not consent to anything remotely resembling the timeline proposed in this discussion for any of my packages. Fork or do not use them if you feel you must.
If you don't trust a developer to ship on a timetable you can support, then do not depend on their packages.
But the flipside of that is that if I don't trust a developer to not spuriously split the community, I can't bring myself to depend on their packages, either.
We lived through the great mtl/monads-fd/monads-tf split and it was terrible with hackage divided into 3 camps that were mutually incompatible.
I personally prefer code that works together to gaining a few days turnaround time or forking for minor differences in design goals.
We've produced a lot of heat from this discussion for a patch that was trivially applied within a week of being submitted.
I think the fact that your patch was graciously applied so quickly by the original author largely speaks to my point, but I'm exhausted by this thread.
-Edward