Elite specs also bring in new ideas for how a class will act. This was expressly talked about during the Profession CDI that happened so long ago, far before Elite Specs, or even HoT was revealed.
For example, Reaper was inspired by Horror movie villians. They’re often slow, but powerful and menacing to instill dread. Reaper reflects that in their slow activating, but very dangerous melee abilities. Berserker was inspired by various fighting games (Smash Brawler’s trait icon is almost identical to Ridely, a trophy featured in Super Smash Brothers: Brawl, other aspects are inspired by other fighting games). Rangers were never known for their ally healing, though they had fantastic personal sustain if built for it. Druid used both GW1 lore and traditional healing concepts to expand on Ranger’s ability to heal allies, pushing them in a new direction (Celestial Avatar form correlates well to Necro’s Death Shroud mechanically, if anyone likes to make inter-professional comparisons. More on that later).
For Guardian, thematically Dragon Hunter expands on the sense of Justice espoused by base Guardian. Sometimes you defend the weak from oppression, but other times you might go out and smite the oppression before it has a chance to oppress. It very much speaks to the Cleave and Smite aspect of “holy warriors”. In modern Tyria, the largest force of oppression are the Elder Dragons. They’re forces of destruction. They’re Monsters that must be Hunted to extinction. Dragon Hunter, incidentally, is very likely (though never explicitly stated) to be inspired by the Monster Hunter series. In Monster Hunter you’ll use a Longbow (or a Hammer, Greatsword, Sword, etc) to hunt things much larger than you, and much more powerful “on paper”. You’ll use traps to capture and damage enemies (Test of Faith, Dragon’s Maw, Procession of Blades) and to support your allies (Purification, Light’s Judgement, Fragments of Faith). Mechanically, Dragon Hunter expands on the Guardian’s ability to control space, or Area Denial. Symbols and Wards were already a good source of this, but weren’t quite enough. Traps expand and improve on that capability, so that with all three (something that DH with LB and Traps has), The Guardian can declare ownership of an area and defend it well. This was/is actually reflected well by a defending DH in pvp matches; where they claim a point, and other classes will have to play around the expectation that there are traps waiting to annihilate them if they misplay. The Symbols and Wards expand that territory and containment. DH fits very well with Longbow and Traps in this regard. There’s nothing about a concept of a Holy Warrior that precludes it from acting as it does (even if that was the case, this could just be seen as an expansion of the idea of Holy Warrior)
For the future, I wouldn’t be surprised of Tomes were the focus, according to the dialogue from devs. Tomes could be implemented a variety of ways (like Revenant’s Legends, or Engineer’s Kits, or others). As far as what aspect of Guardian gets expanded on, or what new aspect gets added, I have no clue. Condition based builds still have an opportunity even though I think Burning can do most of the heavy lifting. Some people want to expand defensive capabilities, and others want to expand healing/support capabilities. All three of those things could even be touched on purely by logical options for Tome design. As far as weapons go, I’m not sure if there’s anything the Guardian needs in its toolkit. Some might say conditions, but I think that would be addressed in a “weapon agnostic” way. Another ranged/midrange option would be nice, but again, not imperative. I think the weapon will largely be the gravy of the new Espec while the overall theme will be the real meat and potatoes. More like Mesmer’s Shield rather than Necro’s Greatword.