I have recovered my "lost" (not really lost) coins by switching back to 3.3.3 (I think these are recently mined).
Don't erase old wallets when you upgrade.
I think the dev team should focus on the good functionning of the coin before improving file sharing : this include fixing problems on the wallet, use of a good difficulty adjustement algo (the difficulty is too slow in adjustements : you may see the delta algo used by guldencoin for instance) to keep the block time more regular...
On the other hand, I still believe on this projetc and I have invested a bit more thanks to the rather low prices.
We've spent the entire past two weeks working on the problems you've been complaining about, and done nothing with file storage or mining pools since people have been having trouble.
We can't switch the difficulty algo, most of the popular ones have problems with other attacks such as difficulty raising attacks.
I'm sorry that everyone feels like switching back to 0.3.3.3 is the safest thing to do. As far as losing coins is concerned, 0.4.x is far safer. The UI has bugs where it won't show your balance (we're working on it), and the consensus database has corruption issues (also working on it - it's done but need to continue testing to make sure no consensus forks were introduced).
I'm sorry the 0.4.x series has been so buggy. . We solved a lot of the major security issues but in the process we destroyed usability.