MMV: Not sure I like this...

[Kunimatyu]

I think you are missing their point. The feat doesn't just allow the person with the feat to make an AoO against the person casting defensively, it prevents them from doing so. This matters when the target is within the threat range of any other hostile figure on the battlefield.

They are not just vulnerable to the person with the feat, but to everyone in the area.

Fair enough, though I can't help but think that just allowing an AoO despite casting defensively would be more potent. (which I'm fine with -- mages don't have a right to get spells off, particularly if they don't have defenses up of their own)

 

[Jhaelen]

Personally, I think the feat is fine. However, I did notice it's banned (or restricted) in the Living Greyhawk campaign, so I am aware it might be problematic should a player decide to get it. I even pointed out the feat (and its upgrade) to the party's main fighter, but so far noone seemed interested in taking it...

 

[Felon]

Esthetically, I dislike the feat on the principle that it operates on the concept of constant one-upmanship. Close-Quarters Fighting (from CW) is another example of this. One person has a feat or ability that allows them to make an exception to the rules, another person picks up a feat that trumps that, and then its escalation ad nauseum.

It's not necessarily escalation ad nauseum. That's a false dichotomy. It is desirable to keep one exception from being all-trumping. Most monsters that have improved grab are pretty impossible to resist due to their high grapple checks. Most casters never have to sweat defensive casting.

Try playing rock, paper, scissors without paper some time.

 

[Felon]

Good idea (a feat that lets a character specialize in harassing spellcasters, such that it's more difficult for them to pop off spells at close range, risk-free) ... poor execution (the caster level reduction and making the action 'impossible' rather than restoring the otherwise bypassed AoO).

Interestingly, there is an epic-level feat, Spellcaster Harrier, that only imposes a penalty on defensive spellcasting, making it rather inferior to this non-epic feat.

 

[Drowbane]

Interestingly, there is an epic-level feat, Spellcaster Harrier, that only imposes a penalty on defensive spellcasting, making it rather inferior to this non-epic feat.

There are a great many "epic" options that are subpar to non-epic material (each new book makes this more and more true).

Several of the Epic Magic weapon properties have sucked since day one.

 

[Glyfair]

Fair enough, though I can't help but think that just allowing an AoO despite casting defensively would be more potent. (which I'm fine with -- mages don't have a right to get spells off, particularly if they don't have defenses up of their own)

I don't see any way you can get his. Please explain a situation where being able to take an AoO against a target casting defensively is better than being able to prevent them from not provoking an AoO.

 

[Mercule]

I loathe the absolute nature of the feat. It runs totally counter to the "you can try anything" nature that 3.x was supposed to possess. Plus, it's just plain annoying.

It would be much better to have it be a modifier to the threatened caster's Concentration check. Either something like a flat +10 DC or change the DC to (15 + 1/2 aggressor's level + spell level) or change the DC to (10 + aggressor's highest attack bonus + spell level). I'm not sure those are the best numbers, but those are the sort of concepts I'd rather see.

 

[Felix]

The feat is fine. The guy still has to get within melee distance.

And a 20th level caster that has allowed his enemies to close to melee with him should be ashamed of himself!

 

[Felon]

I don't see any way you can get his. Please explain a situation where being able to take an AoO against a target casting defensively is better than being able to prevent them from not provoking an AoO.

Well, I suppose the difference is that in the latter case, if you prevent the caster from provoking, he knows what the deal is, and maybe he decides to whip out a wand instead. In the former case, you can pull a "gotcha" on the caster (which is what AoO junkies love doing more than anything).

 

[the Jester]

Mage Slayer sucks, and it has in every instance in which it's been published. It's better than an epic feat (Spellcasting Harrier), ferchristsake!