Like in terms of how useful and good it is and lets assume you have extra reach via either a whip or a Spiked Chain. Is it worth the feat if you have to take most of the side feats anyway?
1 Answers
It’s awful.
Dangerous to even try to use
For one thing, in order to use it all, you have to put yourself in a very bad situation, surrounded by enemies. That is rarely where you want to be. And since it takes a full-round action to perform, you have to spend two rounds there: one getting there, then the other after you have used it. Sure, enemies may try to surround you on their own turns—it’s generally beneficial to them—but then you really want to do something more pro-active than just hurting them each a bit. You need to eliminate some of the danger or remove yourself from that situation. Whirlwind Attack does neither.
Not an effective maneuver
For another, it’s rarely the best tactic for a situation. Usually you want to focus down one target to eliminate them as a threat. Hurting several opponents without killing them leaves all of them fully capable of hurting you back. Killing one opponent leaves your opponents’ side with one fewer option for hurting your side.
The one time Whirlwind Attack is useful to a typical warrior is when you want to mop up mooks: they’re low threat, so being surrounded isn’t a big deal, and they might actually be killed in one attack. But investing considerable resources into dealing with non-threats is not a winning choice.
If Whirlwind Attack had no prerequisites, it would have some niche uses. I would not recommend it in general, but someone who is able to apply status effects on an attack, like a tripper or poisoner, I could see it on. But it does have prerequisites.
Monumental cost
And that, right there, is the final nail in the coffin: “considerable resources” doesn’t even begin to describe what it costs to have the Whirlwind Attack feat in the first place. It requires four terrible feats before you can take it, itself a pretty terrible feat. Combat Expertise and Dodge, at least, do come up from time to time in valuable prerequisites for other things, so you might have those anyway, and Mobility can be gotten from mobility magic armor, which is much cheaper than a feat, so you may even have these feats. But you wouldn’t really want them, and then you have to also take Spring Attack and Whirlwind Attack itself, for another two feats you don’t want. Considering that a non-human non-fighter only ever gets seven feats, spending five of them on this is absolutely not worth it.
It’s also worth pointing out that Spring Attack and Whirlwind Attack are polar opposites of one another. They cannot be used together, both requiring their own full-round action, and really, they appeal to exactly the opposite sort of character.
Strictly-superior alternatives
Tome of Battle presents a series of martial maneuvers, which its classes learn as they level and other classes can learn through feats. These maneuvers are often similar to the things feats let you do, but they cannot be spammed—after using them they must be “recovered.” On the other hand, the Tome of Battle classes get many more of them than anyone gets feats, and they have fewer prerequisites, to boot.
And three of these are improved versions of Whirlwind Attack. They each take a standard action, rather than a full-round action, so you can use one after getting surrounded and then move away. The higher-level ones also get to attack everyone around you more than once, so the damage you can apply is actually significant. And they don’t require you to burn five feats to do it, just a maneuver. Sure, you can’t spam them, but as already established, this is a really niche maneuver—you might appreciate using them once in a while, and the costs of a maneuver are in line with once in a while use. You can only afford to dedicate five feats to something you will be doing every single turn.