sv_slick_applygravity 1 broken
This cvar changes the behaviour of +forward and +back so it takes much longer to reach sv_maxspeed, than it would even on a surface with normal friction. It makes +moveleft and +moveright almost completely ineffective. It makes movement very slow and awkward and prevents the kind of acceleration normally possible on defrag maps with slick. Also the acceleration due to "gravity" it applies on a slick slope, is weak.
sv_gameplayfix_nogravityonground 0 works much better. It allows the direction keys to work normally, and the acceleration due to gravity on a slick slope is about the same as in q3 defrag. However this can't be set all the time, as it causes slight sliding on normal (non slick) sloping surfaces.
A better implementation could work as an exception to nogravityonground 1, allowing gravity to apply on slick surfaces only, since sliding is desirable there.