Uhh, to be honest, I miss each of them for their own individual reasons.

HW - Because every facet of the endgame, regardless of which endgame you went for (be it raiding, crafting, gathering) each of them required a fair amount of interaction, and each was significant in their own right. Back in HW, you could sit there selling Titanium tools for a good 120K per piece, and that was even way later into the patches. I found that I had more of a reason to interact with everything else just because I was a crafter. Had to interact with e.g., Desynthesis, grand companies, fishing, and spiritbonding (it still is, but it was more prevalent back then)to name a few. Relatively speaking you had to work pretty hard, but was equally rewarding. In terms of effort:reward, IMO it was best here.

SB - Because to a degree there was a greater element of skill in the macros and rotations that you were doing. HW for the most part hinged a lot on RNG, but with the variable in stats in SB, you could really spend truckloads of time just optimising macros, especially if you wanted to wince out reuse macros, foodless, etc.,. Whistle While You Work also had a nice amount of engagement with it, and was exceptionally rewarding to master, even if absolutely busted once mastered

ShB - Honestly, Ishgard Restoration. I don't really need to say more... We definitely need more server-wide stuff, the communal aspect of this was just absolutely fantastic, seeing both gatherers and crafters come together for a common goal. Eureka and Bozja somewhat had this, but there was something special with the restoration, especially because of the scale.

EW - I don't think there's anything I'll actually miss if I am honest... I don't think it was a bad expansion, IMO, but nothing really had enough to bite into. Island Sanctuary is great on paper but needed so much more refinement.