Iirc there are really minor difference in a few dialogues.
Starting from the end of ARR, where Estinien recognises you if you started his DRG questline, but is more open and friendly if you've done all the quests up to 50.
I don't really know the rest of HW since DRG was the job I used to get through it (and was the first job to be 50 in ARR as well on my non-legacy account), but I'd guess either it's like that situation with Estinien in ARR, or you flat out need to do the lvl 50 quests to get the other dialogues, since the plot in HW basically takes off from the DRG ARR quests (really, you'll understand more about the overall situation if you do those quests.)