Given the current mechanism, it is possible for users to flood a single region with 1k+ store files via the bulkload API and basically cause the region to become a flying dutchman - never getting assigned successfully again.
Ideally, an administrative limit could solve this. If the bulkload RPC call can check if the region already has X store files, then it can reject the request to add another and throw a failure at the client with an appropriate message.
This may be an intrusive change, but seems necessary in perfecting the gap between devs and ops in managing a HBase clusters. This would especially prevent abuse in form of unaware devs not pre-splitting tables before bulkloading things in. Currently, this leads to ops pain, as the devs think HBase has gone non-functional and begin complaining.