Currently (even on the current iteration of the PTS), stalking blastbones can still bug out and sit next to a target w/o detonating and will do so until its timer runs out. The core issue is still there even w/ the longer launch distance. Furthermore, with the additional launch distance, stalking bb's functionality is probably severely reduced. The problem w/ blastbones sitting there and pondering its life choices seems most exaggerated on small hitboxes or humanoids (minis in vCR+3), but less prominent on large hitboxes (the larger the better - bb works the best on olms and dragons in sunspire, works well on zmaja/AG, but falls apart on small humanoids).
Siphon still has problems targeting corpses and will also turn the character to siphon a corpse, causing LAs to miss and other issues.
Potential fix Ideas:
Blastbones
When cast, let it summon a targetable corpse out of the ground for 1.5s. Upon full assembly at the end of 1.5s (or when stun duration/cc ends if cc'ed) if it has not been killed it will immediately turn into a projectile and launch itself at a target (no longer targetable). This projectile will have a projectile time of 0.5s at <= 5m or 1s if greater than 5m (play w/ the values). Stalkings functionality will be based on the distance the projectile travels (the base skill cannot be cast if out of range or you are Line of Sighted). This should alleviate quite a few problems. To ensure rotations remain fluid, another blastbones can be cast after the assembly phase (so after 1.5s). This ensures it will weave smoothly into existing rotations without having to guess based on distances.
Siphon
Credits to Marteene. Let siphon behave like repentance. If drawing a line in front of where your character is facing let siphon automatically pick the closest corpse and tether it within 90 degrees of either direction of the direct line of sight (180 degrees total). DO still do an animation for siphoning, but DO NOT let the siphon turn your character. Repentance does not turn your character, so go off that model. Characters turning causes severe issues with LAs and skills firing correctly from a static position (namely LAs).
I honestly appreciate the effort in making siphon and blast bones behave uniquely, but I'd rather have blast bones behave like shalks if nothing else at this point since the class just needs to be complete and bug free. It seems pretty clear the root issue causing blast bones to sit there and "ponder its existence" hasn't been ferreted out yet and the players deserve something that functions. In this case a complete rework based on existing skills that fully function seems reasonable.
Godslayer
Tick Tock Tormentor
Gryphon Heart
Immortal Redeemer