If a monster's attack includes a push 1, why shouldn't the pcs be able to use the same arbitrary counter that you're using against Tide of Iron?
It depends entirely on the situation. However, I would most certainly give the PCs a modifier just like I would for the monsters if it made sense.
If you let a monster get a bonus against being knocked prone because he's seen one of the pcs use a 'knock prone' at will a couple of times, do the pcs get that same bonus when they fight a pack of wolves? If not, why not? If so, whoops- those wolves lose a substantial amount of their combat ability.
It's not about them seeing the power being used. In my example, it's about being in melee when that is the only action the PC takes turn after turn. It's not about the PC using the power judiciously, it's about the PC using the power indiscriminately.
To take your example of a wolf. A wolf bites, but not every bite is the same, so the same logic doesn't apply. Although there is a possibility that the PCs could develop a strategy for dealing with the wolves that would give them an advantage.
For instance, and for the record this is a contrived example, lets say that a pack of wolves always bites at the left arm. A PC could wrap clothing, double up armor, or something to the left arm and in those cases I would most certainly provide a modifier.
Limiting at wills like this is a terrible idea IMHO. It nerfs one of the biggest and best innovations of 4e...
That's just it. It's not limiting them. They can use them as much as they want, but they need to do it smart.
I'm guessing you're not going to put some penalty on magic missile, scorching burst or other wizard spells- you're really kicking the legs out from under that balance.
You missed the other example in my first post. It's not the same situation. However, that wizard is going to attract more attention and become a priority target.
The trick to getting tide of iron to work is to hit. The fighter shouldn't have to jump through hoops to pull off what everyone else in the party can manage without any trouble.
There's no jumping through hoops, and if he or she is really good it'll still succeed. It's just a modifier to reflect the PC doing the same thing over and over. I wouldn't apply it if he was mixing it up.
Also- no, there's not one specific way to perform a tide of iron. Maybe my fighter pushes his foe with his shield. Maybe the force of his blow pushes the enemy away...
Well that in of itself would be a rule change. The rules say, "You must be using a shield."
So you don't allow a push against larger opponents?
Did I say that? The rules for Tide of Iron already cover that. You can push a target if its your size, smaller, or one size larger.
You're putting arbitrary restrictions on your pcs. Part of the problem may be that you're reading the term "push" to literally. A push in D&D means you get the other guy to move away from you. It is not specifically a physical push at all- if it were, how would ranged, close or area effects that push you work?
That's a valid point. And very well could be true. The problem here is that we're going off topic on the subject of the Tide of Iron power. It was just an example to illustrate the point that we don't have to limit use of at-will powers, because being pragmatic will do that for us.