The reason I never added quests was because in the beginning, TWBB was meant to be more like Blood n Bones, where the point of the pack was to play in a sandbox while the sandbox was turning to quicksand and killing you over and over again.
The original thread that spawned the modpack's conception basically had TWBB drawn up to be just a "let's throw every mod that makes Minecraft harder into a single pack and make survival insanely difficult to do" modpack. However, over the course of the last year, TWBB has evolved quite a bit, having some actual content mods being included, to focusing more on emulating realistic mechanics (melting temperatures and only being able to cast and recast metals into different forms such as blocks or ingots rather than just crafting them) as and harsh environments (temperature, thirst, sanity, etc). On top of this, FSP and PneumaticCraft were added because there was a rising concern over the lack of actual content and perceived progression (although you could argue that conquering the harsh environment WAS the progression, but I digress). I added those two specifically because their infrastructure included risk (exploding boilers and over-pressurized systems). While I also had Blood Magic included since probably the very beginning, I did it for two reasons - the fact that it fit the theme of bleeding a lot, as well as the concept that you had to hurt yourself (at least to start off) to progress; something that is very precious in the beginning of the game. You have to make the choice to reduce your health in order to gain something in return. This is where the possibility of adding Thaumcraft will come into play, as it provides a lot of utility for the player, but it also has a lot of mechanics that can be tweaked against the player which would fit in better with TWBB's core design.
Now, having said all that, I'm not AGAINST adding quests. I will say, though, that I don't intend on TWBB becoming a skyblock/HQM modpack. If I were to add any sort of questline system, it'd be simply to provide guidance for the player for how to proceed next. Again, you could argue that the difficulty comes with the lack of that knowledge, just as BnB had. BnB didn't have any guidance, and you were supposed to just figure that out on your own. Same here. You know what you NEED to get off the bat - you need shelter from mobs and the weather, and you need food. You could try killing animals or planting crops. Planting crops requires a hoe to make farmland, which means you need metal. Vanilla furnaces won't melt metal as they either aren't hot enough, or don't come with the necessary parts to cast said metal into a usable form. How do you get to that point? a Smeltery (which, is basically a standard in modpacks with TiC, to be honest).
If I don't end up making quests, I'll see about getting some sort of wiki/tutorial up somewhere (I've wanted to do an introductory stream/LP for a while now, but I've been busy). Maybe that'll help?
Again, I'm not against adding HQM and quests, but I don't want to just give out resources for free for completing them. They'd basically be more of a checklist for the player so that they can get a sense of where they are within the pack and what they need to do next.