You do not want to flood hosts with connection requests that really don't accept any connections. I've already read complaints from user who haven't run a Gnutella servent in days or even weeks that they are still hammered with connection requests.
In addition, a malicious attacker could spoof addresses from the download mesh & query hits to use Gnutella as a DDoS tool.
If a host is already overloaded, more connection request won't improve the download stability. On the contrary, the host will have even less bandwidth available to upload and its connections will be even less stable.

These are just a few reasons, why you have to be careful about retrying unresponsive hosts.

There have to be other solutions, to improve connection stability than hammering them.