No, its not all over-complicated hot air. Some good info came out of it. Many find that a straight arm produces the most reliable toss. However, it does not need to be "as straight as possible". Some servers find that a mild to moderate bend in the elbow can also be very effective and reliable -- as long as the angle is not changing prior to release.
The Groth toss action discussed in that thread is not a good model for most players. The flexion angle of his elbow changes quite a bit prior to release. He then straightens it again (almost) after the ball release. Too complex and unreliable for most players, I believe.
If you can lift your tossing arm parallel to the baseline and produce a reliable, well-placed toss, then go for it. This toss direction can make it easier to develop a good coiling of the body for your trophy phase. However, tossing with the arm parallel to the baseline is not absolutely necessary for a great serve.
I do not recommend lifting the arm in the direction of the returner (or the targe area). However, some intermediate angle between this direction and parallel to this baseline can work quite well for many players. Djoko has developed a pretty decent serve since 2010, He lifts his arm at an intermediate angle. So does Raonic.
https://www.youtube.com/watch?v=uyTtZE6LSek
https://www.youtube.com/watch?v=Xzs3cc_rG2Q