Aside from the annoyance of having your original sendmail.cf disabled 8.10 --> 8.11 if you revert to the previous sendmail.cf you have to rebuild the genericstable.db and make sure that the sendmail.cw is re-enabled or all mail just hangs in the queue. After all one would like to continue to send and receive mail until you build a new current .cf, and you cant really do that until the new sendmail is installed. Chicken and egg problem. 8.10/8.11 are not that far apart to have to disable on an upgrade.
sendmail.cw should automatically be converted into the new format. It is recommended to disable a service before an update.
That was a pretty idiotic response. This was during the course of upgrading the entire system to RH7. Of course the service was "disabled" during the update. Just because it worked for you doesnt mean the problem or the complaint will go away.