I look at it this way: there is opportunity, and there is payoff.
Let's say that I have a Strength power that lets me shift 1+[Int mod] opponents.
If I take a 5% chance less to hit (I choose Str 16), I can increase the payoff of the power 25-33% (by choosing a higher Int). Is that worth it? Often enough, it is.
I want my daily powers to hit. I also want my encounter powers to have a maximum effect. Which is more important? I believe that it is far better to support your at-will and encounter powers over your dailies. That's where you get your payback.
When I made my warlord, I noted that many powers affected a secondary ability's worth of opponents. Is that 5% chance to hit a fair tradeoff to shift an additional one or two opponents?
In 4e, payload means far more than damage.