Build a Rogue – The Back-Alley Surgeon

So much like our previous attempt at building a subclass (the Draconic Warlock) we are going to build a Rogue.
The same rules apply as before, we’ll start with a discussion of our concept, and then build the features.

This time we’re going with a Rogue, I am feeling inspired to build a Back-Alley Surgeon, someone who can slice a face off, but also capable of attaching that face to a party member.. in theory.
We’ll begin with our description.

The Back-Alley Surgeon:
Running on the streets, you’ve had to learn the hard way how to keep your friends alive when money ran tight and there was no way to afford a Cleric.
It started simple, you learned how to stitch a wound and disinfect your tools, but soon you could pluck at the threads of life and keep your friends from crossing deaths door.
Maybe you’ve learned how to distil the essence of life into your very weapon, or maybe you’ve a blade that cauterizes as well as kills, all you know is that your blade is one that kills and one that cures.

Next we look at level one, in this we gain a bonus proficiency as well as a feature.

Bonus Proficiency:
When you take this Roguish Archetype at level 3, you become proficient in Medicine.

Life Stealer:
At this level, when you hit an enemy you can steal their life force equal to 1d8, as an action you can us that life force to heal yourself or an ally within 5ft of you (the intent to use this feature must be declared at the beginning of your attack, before damage is rolled).
This feature can be used once per long rest, this features goes up to twice at level 6, three times at level 12, and four times at level 15.
The healing from this feature must be used within one encounter, but multiple stacks of healing can be used at once when you reach higher levels.

Surgical Experience:
Additionally at level 3, with your medical experience you become an expert in dealing damage against one type of creature, choose one of the following creature types, when you roll an attack against them you have advantage against the attack.
Aberrations, Beasts, Celestials, Constructs, Dragons, Elementals, Fey, Fiends, Giants, Monstrosities, Oozes, Plants, or Undead. Alternatively, you can select two races of Humanoid (such as Dwarves and Goblins).

So we’ve got the meat of our Rogue going there, the ability to deal damage but that doesn’t make for a very powerful healer, does it?
But it’s okay, we’re about to hit level 9, and Rogue’s get stronger in their area of expertise.

Resident Healer:
When you heal someone else using your Life Stealer feature, you heal them for the full amount (8hp per use) regardless of the damage done in the attack.
Additionally, Life Stealer’s healing can now be used as a bonus action.

Level 9 has bumped the Surgeon up as a healer, but I think now we’re approaching level 13 we can get a little better.

Skilled Surgeon:
From level 13, the healing from your Life Stealer feature now expires over a short rest instead of an encounter.
Additionally, you can expend one stored use of your healing and as an action, you can make a Wisdom (Medicine) check on a creature with the poisoned condition against a DC of 12. On a success, you remove the condition.

Level 13 has allowed us to help the party a great deal, at this point we’ve got a clutch healer who can theoretically increase their hits against their “Surgical Experience” enemy, and do a potential 24 (soon to be 32) healing in a single bonus action!
So how do we tweak this class and make our capstone worthwhile? How about we add some more poison based abilities

Toxicology:
At level 17, as a bonus action you can convert the stored charges of your healing into a toxin to use against another creature (apart from the one you drew the charge from), when you make a successful attack you can add your stored 1d8 poison to the damage for each charge used (this is rerolled due to the change in type of the charge).
A creature subjected to this toxin must succeed on a DC 13 Constitution saving throw or be Poisoned for 1 hour.

So where does this leave us? Well, that’s complicated, I love the concept but I think I need to polish the execution, but luckily for me there’s no push on the publishing so by the time you read this, my entire current paragraph won’t make sense any more.
But just in case something else comes out first, remember that the Back-Alley Surgeon was the second.
My current hesitation rests on the feeling that I am missing something here, originally I thought I was dropping Toxicology into the mix with no prelude, that there was no build up to dealing with poison but I had already added the poison handling in to Skilled Surgeon and there are plenty of final subclass features that don’t even have that small amount of build-up, so I just need to stop second guessing myself..