I love the concept of conditional abilities which depend on Patrol Zone placement - they emphasize one of the best new mechanics in the game. Therefore Codex should have a lot more things which have abilities along the lines of Debilitator Alpha, and those things should happen at the Hero, Spell and Tech I level where they can be parts of combos and might happen before you need to be teching your win conditions.
As for power level, Codex’s card list is so compartmentalized that it is trivial to see how it compares to all the other $5 Tech II units in the game:
Oversized Rhinocerous - Rhino kills Debilitator with HP left over regardless of patrol zone
Ogre Recruiter - Whichever unit is in a patrol slot defense wins a straight up fight. Debilitator’s ability is easier to set up, but Ogre’s is more generally impactful.
Rememberer - Debilitator wins in a straight up fight, but Remember’s ability is all card advantage meaning that the Peace player is now on the offense with a defensive unit.
Hyperion - Unless either is in the Elite slot, these have to tussle twice to mutual. If the Hyperion is the attacker, that’s +2 card advantage for the Present Player.
Tricycloid - Even against a SQL Alpha, the Tricycloid gets to mutual with it AND do another point to something else.
Void Star 5/4 - While this is probably flying over the Debilitator to to 9 points directly to your base, let’s assume the Future player doesn’t spend 4 more gold than the Peace player – in which case it’s possible that it might just take two turns and no extra gold to kill Debilitator taking zero damage in return.
Mind Parry Monk - whichever unit is in a patrol slot wins a straight up fight. The monk’s ability requires you to have additional units to benefit, but isn’t defeated by sidelining.
Harvest Reaper - If and only if Debilitator is in SQL it mutuals with the Reaper in two attacks. If Debilitator is in Elite, it mutuals with Reaper in one attack, but a point of Overpower damage gets through. If the Reaper is in a patrol slot, then it outright wins.
[*]Grounded Guide - Debilitator wins in any one on one where the Guide is neither in SQL no Elite, in which case the Finesse player gets a draw.