Should I allow a player to use these stunts?

[Wordmaker]

Fair enough. I've seen Presence used a few times, though.

[Sanctaphrax]

The Endurance stunt actually breaks the rules of creating new stunts, because the effect you're getting combines the defensive trappings of both Athletics and Fists/Weapons, rather than just a trapping from a single skill.

I agree with the general logic, but I feel I should point out the fact that Athletics's defence trapping also works against melee attacks. Not all trappings are created equal, eh?

Generally, the stress track skills (except Hunger) tend to be limited in scope. I think it might have been once or twice I actually explicitly used those skills in a character.

That's not my experience.

I like to throw poisons and extreme environmental conditions at people. Makes Endurance a standard defence skill.

And I've found Presence's Leadership trapping to be pretty handy. Charisma is useful sometimes too.

As for Conviction, it's useful for Powers. Rarely comes up for most mortals, though, I'll give you that.

If it can't stack with blocks, it probably needs some other boost.  Weapon rating is a heck of a lot easier to come by than armour.

I'd rather be conservative with the power level of a stunt that lets you defend against all attacks with Endurance. Better to make it too weak than to make it too strong.

Yeah, and I'm wary of letting my players take it without having a character that really suits it. I know it fits the rules, but I still prefer to have the player come up with a decent justification for character builds that can do so much with such a limited range of skills.

All character builds should be justified. Strong ones don't need any extra justification, and weak ones don't get to get away with lame rationales.

[Wordmaker]

Definitely, all trappings are not created equal. It's worth double-checking each custom stunt choice in light of the character's overall build.

[Sanctaphrax]

It's worth double-checking each custom stunt choice in light of the character's overall build.

I don't think so. If you've written your stunts correctly, they'll never be broken in any build.

[Wordmaker]

Even the core stunts and powers can result in an unbalanced build. It's always worth making sure everyone's on the same page and wants the same thing from the game, so you don't end up with one character dominating every physical conflict in a game where the other players want physical conflict to be a dangerous challenge.

[Sanctaphrax]

That's because some canon stunts and powers are badly written. The solution isn't to police individual characters, it's to write better.

Even with well-written Powers you still need to watch out for groups that don't work well together, of course, but that's a separate issue.

[MadAlchemist]

 In regards to using Endurance for defense, I have some long earned GM tips; It can be remarkably disappointing to have the desired mechanics of a stunt shot down or replaced. Often you are better off adding to the work your player has done. It could be toned down by requiring some form of armor against the attack and limiting it to fists/weaponry attacks. If the player wants, that stunt could be a prerequisite for another stunt, like footwork, for ranged attacks.

 For example: Second Skin/Rope A'Dope/Chivalrous Defense ect.
You are adept at using armor to protect yourself, turning killing blows to scratches on steel.
Whenever you are benefiting from an armor rating (or wearing armor if you want to be even more restrictive) you may defend against Attacks with Endurance as if it were Weaponry. Using this stunt against an attack that can bypass your armor rating results an an automatic Terrible defense.

If the player gets cocky drop an npc with an armor piercing stunt or "called shots" to bypass worn armor. If you allow this to work with Toughness, you have a Catch.

 

[Aminar]

Personally I would say go with it.  I wouldn't allow the second one without it fitting, but the first.  hell, why not.  But I D/GM more by rule of cool than anything else.  I mean, sure it doesn't fit every character but I can see Hendricks having Endurance for defense.  Especially given the fact Stress isn't damage.  He's using his bodies bulk and pain tolerance to ignore grazes and near misses without slowing down.  Makes sense to me.