mail clients - why is there no decent mail clients?

Well, I've moved from Kmail (randomly deletes mails, no IDLED support) to thunderbird. Thunderbird is nearly working, but there's a few bugs which I'm listing here mostly for myself to track.

bug #23394 - really old bug - reply to quoting just selected text

bug #116075 - quicksearch including threads

bug #345040 - imap messages don't get marked as read if you move to the next before it finishes loading

bug #345089 - editable 'from' field

bug #345102 - ability to assign an identity to a mailbox

bug #253853 - thunderbird stupidly assumes that if I want to view mail in plain text I'll also want to do the same with RSS. Crazy

bug #345092 - Asks for password for each feed that needs it each time you open thunderbird, despite having told it to remember the password (it remembers it, I just have to click ok)

bug #206408 - thunderbird reports 'Copying message to Sent folder' until you click cancel, upon which it tells you it has not sent the mail, but it has - it has also copied the message to the sent mail folder, so it's lying and just being stupid

bug #179033 - the inability to watch threads in email, although.. you can do it in news, madness

Note to anyone writing a mail client (please please, someone do this before I have to do it myself) I honestly think that there's a hell of a market yet to be fully tapped, e-mail is becoming such an important part of life, people need the tools to deal with it with ease

http://www.xs4all.nl/~js/gnksa/gnksa.txt

It's amazing how there's such a lack of decent, cross platform, powerful, GUI based (yes, I've tried mutt and pine too, both suck, mutt less then pine - but I still have my issues with it).

UPDATE 14/03/2007: Seems I'm not the only one in despair about mail clients being annoying. Over on Mysql Performance Blog there is a post about mail clients and how they should be using a database to store mail. It's a good point - I think mail clients are missing a trick here - not only would it be quicker to search on headers, but imagine having a full text index on your mail - a bit like google mail. I can't be the only one that spends ages searching for specific messages in my mailbox?