Username or EmailPassword
Surely you are joking. Using "I'd write a bash script" to defend a feature, which tries to be a usability feature.
On one hand, you claim it is a good feature for the regular user, for whom it is too hard to do (click synaptic, type string, select, click install), on the other you expect him to go to forums, copy/download a bash script and run it?
Get your arguments and expectations of a "regular user" straight.