It is simple, mutants are not gone and retail system is fine as always.
U dont see mutants, because almost in all cases a main char is better than mutant. So ppl almost dont use them.
There are some exceptions like de/pal - but only at "big bosses" and only at full buff (sos inluding)
wk/sws as a buffer to a pair with se/bd, as long as u dont go pvp or 80+ instances
unfortunately a dwarf is always better at main. About your weapon DS +10. If its Demon Splinters, make it full atribute, if its Dragon Slayer...its useless.
However, if u still want to make some mutant, its easy. Just make a retail in an old fashion way, starting from reorin - cabrio // toi bosses // magister ladd (Ivory Tower 4th lvl) after u finish the quest u can take almost all retails, these which u cant take, u can sub with this u can (u just cant cross old fashion classes with kamaels).
When u pick your new retail, u are lvl 40, exp it up to 78, make 3rd class get a horn, go hardings academy or Ivory Tower lvl 2, and u can sub your retail as u wish. Thats all.