It's fair to criticize my somewhat harsh and yet hard-analysis-free critique. But let me explain why it matters to me, and what the relation to Redis Sentinel is:
"Redlock" is a fancy name, involves multiple nodes and some significant logic, less experienced developers will assume it's bulletproof.
"Redis Sentinel" is a fancy name, involves multiple nodes and some significant logic, less experienced developers will assume it's bulletproof.
I guess I'd prefer that people shoot themselves in the foot with their own automatic failover schemes, instead of using a publicized ready-to-use system which has marketing materials (name, website, spec, multiple implementations) which lead them to believe it is bulletproof, and these systems end up being used in for a bunch of general-purpose cases without specific consideration for their failure modes. In this case, the "marketing" is just the fact that you're behind it, and redis really is solid for what it is.
(Usually I avoid automatic promotion/fail-over altogether. It's often not a good idea. Instead I find some application-specific way of operating in a degraded state until a human operator can confirm a configuration change. So service is degraded for some minutes, but potential calamity of automatic systems doing wrong things with lots of customer data is averted.)
It's really not your responsibility to make sure the open source software you offer to the world for free is used appropriately. But people like me will be annoyed when it contributes to the over-complicated-and-not-working messes (not directly your fault) we have to clean up :)
One specific comment: http://redis.io/topics/distlock notes the random value used to lock/unlock to prevent unlocking a lock from another process. But at that point, the action just before the unlock could very well also have been done after the lock was acquired by another process. So while this is a good way to keep the lock state from being corrupted, it is really a side-note rather than a prominent feature, since if this happens, the data the lock was protecting could well have been corrupted.