Toss the striker
I had to go with controller. in my limited experience, at lower levels, it feels like it boils down to being "good against minions".
Considering minion to-hit and damage. it seems with a dragonborn and a ranger or ftr in your group minions just arent much of a threat.
has anyone found controllers gain importance in higher levels? i havent played through that.
While controllers are good at AoE damage, which means they are good at minion control, that's not the
only thing they are good at.
They can split up your foes, allowing you to defeat them in detail. A few slowed or immobilized opponents really complements a defender. Having an enemy leader split up from his mooks and minions so he can't boost them is gold.
You can do without a striker. It will hurt, and you probably will go through less encounters per day both because you're trotting out dailies more often and also because you'll eat through more healing surges since your foes will take longer to drop. But strikers are about damage, and the others are about (less damage) plus other stuff. Heals, buffs, debuffs, etc.
I still see a lot of 3.5 thinking where "offense is the best defense" and killing the opponent fast (say 1-2 rounds at high levels) is king. That's not what happens in 4e, and damage isn't king. It's DARN useful and important, but it doesn't trump as much as it used to.
You need a leader, though you might be able to get through with a paladin (minor healing) and a fighter (good at self healing) for two defenders.
No defender is rough. Maybe an all striker/leader party that tried to kill quick and had an abundance of healing could deal. And a controller besides the rather fragile wizard.
Hmm, the more I think about it, each of the roles has at least one other role that if you double up on you can manage with.
But still, if I had to skip one, it would be a striker.
Cheers,
=Blue(23)