My issues with Specter may be just frustration based but I'm going to try to keep it tame on it:
Under the effects of quickness, Eternal Night doesn't speed up. This ends up causing a strange feeling while in shroud where all skills are quick except this one move and feels like a punishment for using it under quickness.
I understand Specter's usages of wells are Shadowstep first to the spot, then blast the area with magic. However the cast time and how the order of things goes(Shadow Step first, then drop bomb) ends up making them almost not usable inside of PvP without stealth(which may be intended). The issue I keep finding myself hitting in PvP is not only do I cast the well, I'll end up being downed in the process, but the Shadowstep occurs causing you to go to a diff location without the magic bomb occurring either. It feels somewhat unintended if you are downed before the shadowstep to be moved when you are still casting. Or maybe there is that split second that I seem to hit in PvP matches where I get downed without getting the well off.
Shadow Shroud's Bar doesn't have any indicators on it...and I dont recall but I think Necro's does? There isn't really a way to gauge how much 'HP' one has left. Everything seems % based in tool tips as well, but it does act as a separate hp bar
Rot Wallow Venom suffers from the Untamed's old situation. To explicitly use this on any weapon outside of Scepter, you MUST take Shadestep to be able to burst your barrier. There is some dynamics to this that leads to the Specter needing to have Barrier applied, to be able to apply barrier, and if the Specter is getting barrier from someone else, they are probably providing barrier to the party already. So for other weapons(Daggers, Pistols, Shortbow, Sword) it feels as though you will apply stealth to the team in mid-combat just to apply the Rot Venom. Only traits I can think of for this are Blinding Powder and Stealth Refuge, and if I recall the healing from Stealth refuge is pretty small. The only other way that seems more in line with Specter is to be forced into taking Shadestep, removing the ability to be a bruiser from the top trait, or to consume conditions for heals with the other trait. It feels like other weapons are punished for being played with Specter. In the Guild Wars 2 Partner Discord Community, I'm getting the feeling most users are unanimously saying Scepter is strictly the only weapon to use, which seems to be the untamed's old issue.