We started talking about this at this month's chat. I'd love for you guys to talk more about this, especially concerning actual PHP namespaces and possibly PSR-4 autoloading and whether that makes sense for loading add-ons.
Somewhat along those lines, whether it's possible for ExpressionEngine to enable or encourage add-ons to use Composer. I know some add-ons run into issues when another add-on is used that shares a common library. (E.g., https://github.com/click-rain/EE_Twitter/commit/66bcf5c875ee4f02484b0ab19ed45ba6fdc499be.) There's been some interest in using Composer: https://twitter.com/BryantAXS/status/532669889870573568, https://twitter.com/leevigraham/status/359658312981164033.
Almost every add-on includes installation instructions which typically amount to "Copy this folder into third-party, copy this folder into themes, press install." It would be awesome of there was a solution that took care of this 90% case, possibly by pulling folders out of pre-defined locations from a zip file. This also would prevent the need for FTP access in certain situations when installing add-ons.