Guild Wars 2

I’m sure this has been said somewhere before but I couldn’t find it. With the release of specializations, will we be able to mix our core skills with the specialization skills? For example, will I be able to have say Flesh Golem as an elite skill while specializing in Reaper, and still have some reaper skills in the rest of the skill bar?

Yes.

In the dragonhunter video the devs used some guardian skills along with DH skills.

The Default skills will still remain but the main thing changed will be the Professions main unique system such as how Guardian gets different Virtues as a DH and Necro gets a new Dark Shroud as the Reaper.