I don’t have much to add to the questions but I want to show my support for this line of thought. The conditional move should be conditionally better than other moves when used correctly, with the addition that the condition needs to not be super easily met (say opponent having an item, your mom being level 100, having terrain or weather up). Or to put in other words the activation of the condition for this moves requires skillful use and if used correctly has a payoff that can’t be replicated with other moves.
Double Shock
Condition: This move fails unless the user is Electric Type. The users Electric Type is removed upon successful use (unless the user is Terastalyzed)
Consistency: 100% on first activation, 0% on consecutive activations.
The consistency issues of this move come from having to switch out or terastallize to reload the condition and from having to deal with Pokémon immune to the move. This means the condition is in full control of the player and thus has 100% consistency potential but at the same time forces awkward play patterns, which creates inconsistency.
Payoff: The most powerful physical Electric move. The removal of the electric type can also be situationally helpful.
Constraints: The user will have to be an Electric Type and a physicalist mixed attacker. Also this moves likely benefits from a role that wants to switch a lot (though it might be more interesting on a Mon that wants to stay in for longer periods of time.)
Why do I like this move in particular?
I like the idea of a move that has immense power and a condition that the player can control, but at the same time forces potentially awkward plays from the user, to stay in control of the condition. Reloading the Electric Type through switching can lose the player momentum, while staying in removes your most powerful attack. It also has to play around Ground types soaking up your nuke. Lastly it has an interesting interaction with Terastalliztion, which gives another layer of control while at the same time once again forces the player to make a decision wether this finite resource is worth using in that moment.
TLDR: Double Shock is a conditional move which the player has a lot of agency over activating that condition.
At the same time this agency requires the player to constantly evaluate the cost and payoff of retaining control over the condition this move requires, which introduces a layer of skillful use that I think makes conditional moves actually interesting.
Since my favourite options have already been suggested, mainly for the sake of completionism, I would like to suggest
Burn Up in addition to Double Shock, while at the same time throwing some
support behind Double Shock.
Condition:
This move fails unless the user is Fire Type. The user's Fire Type is removed upon successful use (unless the user is Terastalized)
Consistency:
Works once and only once every time the user switches in, unless the user Terastalises Fire. It loses the ability to use Burn Up entirely if it Teras into another typing. At first glance, it might sound too restrictive to make work, but in many cases, it's a more lenient First Impression.
Payoff:
Here’s where Burn Up would differ from Double Shock. Unlike Double Shock, which has little competition in the Physical Electric pool, there are other good Special Fire attacks that Burn Up competes with, notably Flamethrower/Fire Blast for spammable options, and Overheat for nuke and run options. Burn Up is essentially a variant of Overheat that trades not reducing SpA by 2 stages, for removing the user's Fire typing. And there are real and tangible applications for removing the Fire typing that I will explain in a later section.
Constraints:
The biggest constraint here is obviously the fact that we are locked into a Fire type. And I guess the other constraint is that we have to consider how it is going to match up with Flamethrower/Fire Blast/Overheat on a user.
Why it's interesting:
I think there are 3 very distinct ways of abusing Burn Up. The first is one as a pivot, which plays around resetting the removed typing to drop a nuke everytime it comes in, in a way similar to Dragapult with U-turn/Draco; The second is as a Tera nuker, who abuses the interaction with Tera to spam the move without having to reset the typing; The third is one which can make use of losing the typing to bolster it's defensive profile.
The Fire typing is a pretty interesting typing imo. It lowkey has one of the best set of resistances, while also some of the most painful set of weaknesses, so there are strategical benefits of losing the Fire typing. Something like Rotom-H or Heatran, for example, would be happy to leverage the Fire typing's useful set of resistance to switch in, and then discard it to remove the weaknesses associated down the line to better deal with a Water type.
--------------------
From a logistical POV, I think the main problem with Burn Up is that it's a dexited move, so I'm not sure if it is allowed. And if it is to be allowed, I'll leave it to the topic leaders if they want to slate it with Double Shock as independent vote options or lump them together to decided on at a later timing.
Edit: dexited is real
But sure, what I have said for Burn Up applies to Double Shock as well, so pretend this entire paragraph is shilling Double Shock lmao.
As an aside, after looking at some of the slates for other moves, I think
Eruption variants are probably my favourite (even more so than Burn Up/Double Shock, which offers a lot of extremely interesting build-arounds that Askeia as mentioned in their post earlier; and maybe
Beak Blast, tho I do feel less strongly about the latter than I did a week ago.
--------------------
As an aside aside, I still can't find a compelling argument to "focus" on Tantrum/Temper. I agree with Guingil and Shock3600 that by nature of being a punish to immunities, these moves are more of a complementary tool rather than being a primary target. The best user of Tantrum/Temper is probably something that doesn't focus on them, but rather one that focuses on a more spammable move and just happen to have these in their learnpool. What is the deciding factor that would make CAP37 more "focused" on Tantrum than Astrolotol for example?