In the case when `mongod` hits connection limit it stops accepting connection both from clients and from other replicas in its replicaset.
When something particularily bad happens on MongoDB replicaset and `mongod` exhausts connection limit, the only way to restore replicaset service is to restart all `mongod` processes.
I consider `--maxConns` in its current state harmful for replicasets. I propose two ways for fixing the issue:
1. Either reserve some quota for replicas or by any other means move connections from replicas out of connection limit.
2. Forbid usage of `--maxConns` for replicasets.