I think you're using a rather liberal interpretation of that part. It refers to the power's effect (as in what happens when you use a power in question), not an effect line in a power. The example given shows what you're saying to be false (it talks about not letting a warlord power buff an entire army, as it is only intended to buff a party).
As I mentioned before, the idea behind the entire paragraph is "Despite what the rules say, don't let players get benefits from powers when used outside of a 'normal' combat". It basically says, don't let them heal by hitting a rat despite the fact that it is legal in the rules, because a rat isn't a threat. Don't let a power affect 100 people despite the fact that the rules allow them to, because all the powers were written assuming a group of 4-6 players against a group of similar level enemies.
It may not say it in as many words, but I think a similar philosophy applies to powers that have an affect and are meant to be used in combat (obviously....they wouldn't have attack, damage and target lines if they weren't).
You don't find the slightest bit of irony in the fact that you are looking in a paragraph that says "Don't always follow the rules to the letter when it's clear there are times they shouldn't apply exactly as written" and saying "It mentions effects that happens on a hit, but fails to mention effect lines....we must follow the paragraph exactly as written"?
And then in the same post point at the rules for targeting empty squares in order to find invisible enemies and say "It says we can target empty squares. We must follow those rules exactly as written."
Except that page 272 clearly states that targeting a square is legal.
A rat is a legal creature. You can clearly target it. Clearly you should get benefit for hitting it. Except the section that says not to give benefits out in situations they weren't designed for(which it gives 2 examples of: Hit effects and affecting too many creatures).
I'm wondering why preventing people from using powers that have an effect on hit was considered abusive enough to write a section on it but powers that have an effect line are not abusive? I mean, why does the ability to heal someone on hit as an encounter power need to be restricted while another power that heals people as an effect on top of the attack not need to be restricted somehow?
Regardless, Firelance has already demonstrated that this is false. Nowhere do the rules say that you need a target to use a power, and every indication is that you don't.
Hey, I can play this game too.
I have already demonstrated that this is true. Nowhere do the rules say that you don't need a target to use a power, and every indication is that you do.
Considering there is about as much evidence one way as there is another. I haven't seen any indication that you don't. I think the entire fact that there IS a target line, a section in the DMG saying that it can't just be any legal target(that the DM should reserve the right to say NO, not THAT target), and another section saying that you can only target objects with powers that target creatures with the DM's permission is extremely strong evidence that you need a target.
FireLance said:
In fact, the description of "Effect" on page 219 of PH2 states:
Anything that appears in an "Effect" entry occurs when you use the power, whether or not you hit with it, if it is an attack power.
That's correctly. If you hit or miss with the power, the effect goes off. If you don't attack at all because there is no target, then you neither hit nor not hit with it. So no effect happens.
My main argument against the effect line to happen with no legal target is that the goal of 4e was to "silo" in combat powers away from out of combat powers. They did this by dividing powers into Attack and Utility.
A bunch of the articles before 4e come out explain that the goal was to prevent players from ever having to make a choice between in combat utility and out of combat utility. They didn't want someone to have to decide between, say, Disguise Self and Magic Missile.
If you allow people to use Attack Powers when you are not in a legitimate combat, then you are once again forcing people to choose. There is a difference in utility between a power that does 2[w] damage and then lets you teleport 5 squares only in combat and one that does the same thing but also lets you teleport 5 out of combat.
Likewise, there is a difference between a 2[w] with an effect of all enemies adjacent to you grant combat advantage and a 2[w] with the effect of teleport 5 squares if you allow the effect line to work out of combat. When you choose between the two powers, you are now forced to choose between in combat and out of combat utility. Is the ability to have enemies grant combat advantage to you while in combat equal to the ability to have tactical movement in combat AND teleport essentially at will outside of combat? The same thing happens when one power has an hit effect while another has an effect. You can't use one outside of combat, you can use the other.
I just think it's unfair to make people choose. It's especially unfair to tell one player: "Sorry, all of you powers have on hit effects or effects which don't matter out of combat. When you are out of combat, your options are limited to your utility powers. You can choose to do one of those 3 things there. But, lucky you, all of your powers have effect lines. You get to choose from 6 different things to do outside of combat."
To my mind, the emphasis on hitting is to distinguish "Effect" entries from "Hit" entries: you get the benefit of "Hit" entries only when you hit a legitimate target, whereas you get the benefit of "Effect" entries simply by using the power. 
