Yea, I can see that... . The problem though is that it might create a lot of warn messages... . People can always decide to dynamically enable debug logging here to see whats going on. We do not allocate shards on other deciders, and never warn because of it...

One of the things we were thinking about is that potentially part of the reroute call, we will give back a full explanation on what was allocated and what was not, so people can see it as part of an API call about why things were rejected.