Oh. AFAIK it worked as a design, so it wouldn't have been a waste and I think Calbear is wrong.
Okay.
Most of this was covered back when the original T/L was posted, but...
Pre-computer assist flying wings were great places to find the name for Air Bases (the B-49 gave us Edwards AFB) and little else. The are great right up until they aren't, then they kill you. The flying wing has a tendency to become divergent on all three axes, that is one of their biggest advantages for combat, they are dynamically unstable, allowing rapid maneuvering that a conventional aircraft can not match (as an aside, this same sort of instability is built into the F-16 design, without fly-by-wire it is a smoking hole waiting to happen). This fatal problem can be prevented by continuous, near instantaneous, corrections to control surfaces (unfortunately these corrections are necessarily faster than human reaction time, and need to take place on multiple surfaces).
Four decades of research by the U.S., USSR, UK, France, PRC, and private efforts at the height of the Cold War say that the entire concept wouldn't work without fly-by-wire technology. One TV documentary says it would. I'm liking my position here.
The research cost is extrapolated from the V-1 & V-2 program, which cost roughly $3B 1944 USD (about 150% of Manhattan or ~5B RM). Hitler would spend whatever it took once he decided he wanted something to work. even if it wouldn't work or if the RoI was beyond pitiful. Far beyond any of the other major political players of the era, including Churchill (which is saying something), Hitler was cursed with a severe case of "Oooh! Shiny!". Worse, unlike any of the other players, he listened to absolutely no one, about anything, once he decided it was good idea (even Stalin could, occasionally, be persuaded to reconsider a course of action, provided it wasn't political). Hitler displayed this IOTL even after he was losing the damned war, if anything the tendency became more pronounced as thing went into the dumpster. There is absolutely no reason to expect that a victorious Fuhrer would be more accommodating to the opinions of others.
As far as the "idiot ball" - The Nazis were, IOTL, saddled with the largest idiot ball seen since Ala al-Din Muhammad II of Khwarezm gave Genghis Khan's ambassadors their haircut.
It was incredibly difficult to figure out a way to reduce their stupid far enough to get the original T/L (i.e the "Preface" in the posted T/L which was supposed to be the whole project) to work. Had to find POD that kept them out of Africa and the Med, got them to send winter clothing to the troops, had Hitler rein in the the other fascist idiot so there would sufficient troops to actually make Barbarossa workable, etc. The Reich would find a play they liked, and they would keep running it, even when it started to get stopped at the line of scrimmage. Some of the General officers were very clever, innovative, and flexible. This being said, the higher one went in the command chain, especially once you entered the political strata, predictable was their watchword. This, BTW, was why
Wacht am Rhein worked as well as it did, it was utterly out of character (except for the reality that it, well, ignored reality, in that way it was classic Hitler reasoning). In an
AANW world, Hitler would have more or less retired out the General Staff whenever possible (age, illness, whatever) and replaced those officers with those of greater political reliability (his distrust of the General Staff is well documented) without much concern about military skills, after all, Hitler was his own CiC. It is worth keeping in mind that Hitler gave Himmler, of all people, command of TWO Army Groups (Upper Rhine and Vistula) so he was a less than stellar judge of military acumen.
To the original question... without the Horten Brothers siren song the Luftwaffe would have wound up with a lot of rocket and mixed powered point interceptors (when they would have figured out the whole supersonic issue is an interesting question, especially in a practical design) and eventually the Ta-183 or some similar design once they managed to get the bugs out (the Ta-183 was another one of those "cool beans I love this- OH SHIT!" designs).
