New Vegas didn't have crafting? NV had a wide range of things to craft. Weapon modification, ammunition crafting that involved converting different ammo types and creating special ammo types, and cooking a variety of food recipes and chems. Compared to its predecessor Fallout 3, New Vegas improved vastly in crafting and modifying, so I'd say it did well enough. And even then, Fallout 3 had its own crafting to a lesser extent with a handful of unique weapons.
As for everything else, no, Fallout doesn't need a skill tree, because this isn't TES. It doesn't have weapon enchanting either because this isn't TES. The new system in Fallout 4 revolves entirely around your attributes that determine what perks are available to your character. The extent of some crafting seems to rely on what perks you have and how much you've invested into ranking it up.
As far as crafting goes for Fallout 4, BOX MAAAN said enough. Even with what little information we have, the crafting in Fallout 4 already seems like its far beyond anything Bethesda has done in any previous game. Weapon crafting that goes so far as to turn a measly laser pistol into all different kinds of variations of laser weaponry through numerous modifications and creating those modifications from just scrap, building your own settlement the way you want it. Honestly, the settlement building alone sounds like more of its own game than anything in Skyrim.