First user is asked to enter nickname; he can't get back as 'cancel' button will just prompt the input again. Then user faces a password field in a harsh way, no link for subscription and way to change username.

I'd say to move nick input in the same ask_password.cpp dialog.

this should be closed as of http://code.google.com/p/hedgewars/source/detail?r=70e980278080ad60e795a79faffdefd4a6356ff5

yup, indeed