Email size is a technical issue that shouldn't be limiting (or even visible) to the end user. If an end user wants to send a multigigabyte file to another user's email address - why not? The email client could launch a background upload process and email a link to get that file by, say, bittorrent... Some protocol extensions and software support would be needed, but that can be done and, as users need it, probabpy should be done.

Oh, the protocols are already in place; consider RFC2017.

Sending a link to something (even wrapped in a nice ui and container) has pretty different semantics from actually sending the something, though.

Opinions run the gamut. I'm firmly in the "email should be plain text" camp but realized that battle was lost long ago.