It's debatable. "Core" GW2 is a fairly bland sampler compared to 2015/2017. The game only gets better with HoT/PoF. I'd strongly suggest trying out Elementalist, Engineer & Mesmer as these are the least standard classes in core.

There are lots of people that'll argue that "core" is essential to the GW2 experience, and in a sense, it is. You'll get lots of casual, exploration and story-focused content, but the overall difficulty level will be about a 2-3/10. There are many people that argue that "core" GW2 is a tutorial for the rest of the game.

Yeah... I disagree with that. GW2 has a lot of really unintuivie, poorly explained systems such that lots of newer players do boost to level 80 and wander around on bad builds that constantly struggle with the modern open world or story content. If you boost you really need to get a build from "MetaBattle." and make time to skim over the MightTeapot overviews (which I've linked you in the prior paragraph).

Combat in GW2 jumps up to about an 8/10 in HoT and a 7.5/10 in PoF. It's a significant boost for which core GW2 does little to prepare players for. Upon HoT launch in 2015 the difficulty was a massive turn-off for casual players that wanted more idyllic exploration. The difficulty has since been toned down a bit.

For a lot of veterans the idea of playing GW2 without elite specializations is unthinkable. They're game-changers that expand upon and open up new class/profession-mechanics that offer more depth & breadth of gameplay.