As far as the worst loss type of discussion, I don't care enough about other teams to really get that invested in the who Alabama lost to stuff. I didn't take Auburn losses as hard as some people for that very reason, I don't care about Auburn, I only care about how it influences Alabama. So yes some of those were pretty devastating to Alabama's title hopes, certainly more so than this loss.
The late season losses that knocked Alabama out of contention, the playoff losses, the championship game losses, those are the worst Alabama losses as far as I'm concerned because those are the ones that were the most costly. This in relation to that is just another early season loss.
Most disconcerting loss? This has to be up there, because no, this wasn't like losing to a talented Texas A&M team, or a team coached by Steven Spurrier. This was losing to a team that was vastly inferior in terms of talent, and that makes it extremely alarming.