Yeah, it's a bit weird, but I usually just click "Display as List" on search results pane and then it becomes more usable...
If you're actually trying to encrypt email, you probably don't want your mail app building a search index in plain text.
Just getting a working subject / from / to search would be great. That said, my primary purpose with GPG is securing the emails in transit, not on my laptop. I already use disk encryption and most of the documents I send are stored unencrypted on that disk as well. The kind of people that would break into my computer would most likely just install a keylogger to get my GPG key rather than look for plain text indexes.
Depends if you're primary concerned with transit, vs local storage.