I initially thought this about TSW as well - until someone pointed out a dev post where they noted they were not doing away with the trinity for high-end content but making character builds flexible enough for you to be able to have multiple roles in most of the rest of the content. As a result I am playing a self-heal dps solo, and a tank in groups.
So - not QUITE true - the trinity was always there - it just took a while for folks to see where it was needed, where it wasn't, and adapt.
As for dual-specs - TSW has multiple available - 16 I think? Could be wrong, as noted, I have only explored 2 so far.