I decided months ago I was going to stick to humans and Qunari.
I am. I decided against playing elves the second only dalish was revealed. I'm just a bit hmm that tattoos aren't optional since they were in DAO.
As for X has Y so don't play X one could say the same about humans dropping Andrastian sayings (whether or not they believe in the maker or not such sayings would be a part of how they were raised). *shrug*
I think this time around, they're trying to create a game and a world with more internal consistency. You could also play a blood mage in DAO and DA2, but noone reacted to you, and it wasn't believable. In DA:I, they seem to be making a better effort to stay consistent with the lore and also make all of your choices (in race, gender, class and specialization) things that the world and NPCs in it react to. Personally, I'd much rather my choices matter and lead to people in the game reacting appropriately to my PC, than just to be able to have no tattoos and have no one wonder or comment on that fact.
If you made a tattoo-less Dalish in DA:I, either it'd be the only part of your appearance/character that oddly never was commented on/reacted to, OR the writers would have to add in a bunch of new/different dialogue to explain why you were different than other Dalish. They'd have to rewrite scenes in which people recognized you as Dalish (because without tattoos, how would they know?), and encounters with other Dalish would have to be written differently, since, unless it was your clan, they wouldn't recognize you as Dalish right away either. Even encounters with your own clan would have to be written differently to match the believable reactivity of the rest of the game. If you went home, other Dalish would certainly treat you differently if you have vallaslin vs if you don't.
TL;DR, to make a tattoo-less Dalish work in this game would either take a LOT of extra work/writing/etc, or it would stick out like a sore thumb as the only part of character creation that doesn't fit into the realistic reactivity that they're working super hard to include this time around.