To streamline the registration process further, newly registered domains should be by default set to the public resolver. I could be wrong here, but won’t 99.9% of users be using the public resolver for .eth name resolution? This would be one less transaction for the end user. The new registrar is a big step forward from the old as far as usability, but there are still too many transactions that need to be completed to register a name.
Unfortunately, I think it’s too late in the day to add this to the new registrar - the code is pretty much locked down at this point.
Fortunately, it is possible to remedy this after the fact: the controller can be modified to do this. In the meantime, it’s fairly simple to write a ‘shim’ contract that takes care of registration and assigning a resolver in a single transaction, calling the controller on the caller’s behalf.
I’d rather take our time to add support for this properly, rather than rushing through a change - even a seemingly simple one - without audit a week before release.