@curtismchale - Yes, this is something Otto pointed out in our conversation:

Yes, the yellow/orange 2 year old warning means that the plugin will not appear except in exact-match searches. If your search exactly matches the name or slug of the plugin, then I think it will still appear at the top of the list, but it cannot appear in a search otherwise.

Of course, the author can just update the plugin to get the date updated, so the 2 year warning tends to be indicative of a plugin that hasn't seen any change in a while. This doesn't necessarily mean it doesn't still work though.

The admin notice sounds like a better idea of notifying users. As a user, I just want to be notified any way possible about the last version.