Originally Posted by Alienist
If you're not in it for the -2s, then there isn't a whole lot to get excited over controller-wise...
Iilusionary Ambush + Psychic Lock + Marked by your defender = -6 to hit. If the monster hits on a 13 or higher, now suddenly they hit only on a 19 or higher. That's a big difference.
Making him lose a move action? Not so much.
See, the thing is, making an enemy lose a move action or forcing them to only target things that are already within 4 tiles of them (slowed move+charge)? That severely limits their target options, and melee characters tend to have higher defenses and more hit points than ranged ones. It is, often, more often than a credibly-threatening monster hitting only on a 13+, likely to mean the difference between a monster hitting the squishy members and hitting nothing at all, and even when it's not it's virtually always the difference between hitting a squishy member and hitting a tough member, both more valuable options.
Further, major threats' melee basic attacks that they're forced to use if they're forced to charge to attack their preferred targets are significantly weaker than their other options. Elites almost always have a power that lets them attack twice, but hard control can prevent them from having a good opportunity to use it, while soft control can't. Even standard monsters occasionally have an ability to attack more than once per round at least sometimes, and hard control can prevent that while soft can't.
You're also assuming that the monsters are hitting only on a 13+ before the defender's mark is taken into account, but that will usually only be true on the defender themself, so you're not even really stacking as many penalties as you think.