Because you did not have a Demon Hunter issue section, I'd like to just mention a few that you can add to your post. Please other Demon Hunters verify to prove the legitimacy of these bugs/annoyances you have experienced. I've mentioned some of these to rrrix already, but they could use an official home here.
Demon Hunter Issues
Problem: Demon Hunter continues to over vault until you run out of discipline in combat and dies. Very bad when the radius of monsters is within a triangle equal to the distance of each vault in all directions; at which point, you don't attack at all and just are vaulting around until you die or break the chain.
Partial Relief (not a solution): I've found lowering the kite range helps a little to get a few more shots in for the kill and reduce vaulting occurrences. However, its subjective based on your DPS and if you can take out monsters before they take out you. I wouldn't recommend going much lower than 4 or 5 as that's within most monsters pounding you in the face.
Recommendation: Scooting and shooting more. Also balance out vaulting with running some. Vaulting delay is great when going from A to B, but in combat it can be lethal. Favor vaulting to previous walked areas so you don't vault into molten trails if possible. When disc is lower, favor running from danger like other classes unless you can vault to a near by health globe witin vault's maximum distance. If using gloom, try a few fire off shots and see if life improves, With each vault try taking a shot or two after weighing the situation, then vault again if needed. If your vaulting more than 3 times before firing, its probably a bad idea to continue to vault, so maybe temporarily reduce or stop the kite range activating another vault in certain points of the vault chains so a few shots can be made.
Problem: Demon Hunter will over-vault while waiting for a Molten Core to expire (or any enemy skill that takes awhile to expire). Rather than attempting to run up to the core, the DH simply vaults forward and back over and over again until its clear or runs out of discipline. Sometimes it will vault into the core on accident and die (rarely if you have a higher radius distance set than the default).
Problem: Demon Hunter will vault towards a health globe that is sitting under the elite its firing at simply to vault away again resulting in over use of disc and a higher chance of dying. Will also over vault to get several globes to heal until disc is depleted making DH vulnerable.
Recommendation: Favor health globes that are closest to the DH but avoid vaulting towards the elite pack its firing at if that is the closet globe. If several globes are close and within proximity to one another, favor those and get back to attacking sooner. Choose running over vaulting if the globe is within say 75% of the vault's maximum distance and/or disc is low. If using and under gloom, use that as an alternative to globes occasionally. Once two or three globes are grabbed, stop vaulting as much to give those globes time to work and try firing a few shots and/or activate gloom and fire. More scoot and shoot behavior.
Problem: Demon Hunter mostly ignores Blazing Ghouls and minions that spawn from shamans and will very rarely attack them. Mostly noticeable in Towers of the Damned. This many not be class specific.
Problem: DH fails to avoid demon mines and will stand on them and take the punishment. Likely not class specific. May be DB at fault here.
As you see most of the issues are vault related, so if you don't use vault you probably don't see a ton of these issues. However, I think for speed farming its wise to use vault (especially with legacy nat set) and so I hope this gets some love some day.
