The inability to send large files is pretty frustrating. The alternative services that can serve as a workaround to this problem (dropbox, etc.) are still relatively clunky as well.
These days mail clients like Thunderbird warn you for large attachments, and prompt you to use some other solution. Even better: using the built in XMPP-client they could easily send you infinitely sized files at you@yourdomain.com - if only you would run an XMPP server on your domain
E-mail was never intended for sending big files, it was for sending text. And for that, I think, e-mail is perfect.