The recipe system replaced weapon schematics, but when we reintroduce Fallout 3, it'll still be there.
Workbenches must be the NV kind.
What should we do about schematics though?
We could just make them into recipes, with different recipes for different levels of schematic, but that'd be bad for two reasons in my opinion: one is that the recipe system doesn't allow for the essential repair-skill-based-conditions of Fallout 3 (and I think 100% all the time no matter what would be overpowered). Also, you have to consider that NV made some crafted weapons, like shishkebab, much more valuable and therefore overpowered if you could just make them easily.
Also remember that due to the New Vegas engine's new ammo features the Rock-It launcher is completely broken. It will crash if you try to use it. We have to either repurpose it to use a set ammunition (would be weird) or scrap it (would be sad), or something else.
I definitely want to see Dart Guns Railway Rifles Shishkebabs Deathclaw Gauntlets homemade grenades and even the Rock-It Launcher in some form in Fallout 3 again. However, maybe the crafting of those weapons is better left to NPCs, and they would be fine as only lootable/purchasable?
I vote for keeping Nuka Grenade and Bottlecap mine recipes of course, just worried about the real weapons.
I mean you can obviously tell that shishkebab is made from motorcycle tank and lawnmower blade, but maybe that can just add to realism and wouldn't just raise the question "why can't I craft that" as much as you might think. Besides, it has that nozzle thing, and the other weapons all have stuff like those, parts that aren't in the recipe that turn up on the weapon, which might make it more realistic to just have them NPC-bought and scavenged.