The problem with sure strike is that it doesn't do anything that other fighter at-wills don't do better.
Sure Strike increases your attack roll, meaning you do more consistent damage. Well...reaping strike does damage whether I hit or not, a far better option.
Sure Strike has a bit chance of hitting a minion. Well, cleave can autokill minions and does more damage.
This is a flawed comparions. Cleave does not autokill minions, it autokills minions
if you hit, and additionally, it's only useful if there are two creatures adjacent to you. But there aren't always two creatures adjacent, so what's the point? If you're in a situation which favor's cleave, then it's unsurprising that sure strike isn't attractive. If, however, you're only adjacent to one minion, then cleave is clearly worse. Even if you're adjacent to two minions, you might still be better off killing one reasonably certainly rather that both with a slightly lower probability if the minions have nasty powers based on combat advantage (and avoiding being flanked is thus important).
When is sure strike good? When you want to be sure to, well, strike. If you need to stop movement on an OA (with heavy blade opportunity), or if you're fighting a minion, then the damage difference just isn't important, but hitting is. In combination with other powers, hitting sometimes also becomes more important than a bit of extra damage. It's also important not to overstate the damage difference between sure strike and other options - it's there, but it's not terribly large, esp. if you're wielding a relatively damaging weapon and/or have abilities which can improve your damage in other ways. If you have scimitar dance or hammer rhythm, reaping strike becomes less attracive anyhow; cleave is situational, and tide of iron requires a shield (and is only interesting when pushing an enemy is a good thing).
I don't think sure strike is brilliant, but for my human sword-n-board fighter (which has three at-wills) I prefer it over reaping strike. Is it situational? very. But reaping strike is even more situational; almost always cleave or tide of iron are more attractive, and even when it's the best option, it's only slightly better than a basic attack for a one-handed weapon wielder.
Careful attack is worthless; but sure strike is merely situational and not very good.