Although I love the simplicity inherent in 4th Edition, as you are by now realising, I also miss a lot of the complexity of 3.0 / 3.5. Lately, I have been sneakily introducing some old school conditions into my games, as part of the ongoing move towards more challenging but fair 4th edition.
So, for your pleasure, here are some conditions that I have or will be using. Those with an asterisk (*) are from the D20 SRD.
Confused*: You are filled with clashing thoughts and chaotic ideas, and as such, are prone to unpredictable behaviour. At the start of each of your turns roll 1d100. Consult the following table. These are your actions in that round;
01-10: Attempt to attack the one who inflicted the confused condition on you.
11-20: Act normally
21-50: Scream, gibber or otherwise do nothing helpful (you grant combat advantage)
51-70: Use every means to flee the source of the confusion.
71-00: Attack the nearest creature, regardless of whether they are an enemy or ally
Exhausted*: You are Slowed and suffer a -3 penalty to your Fortitude, and all Strength and Constitution based attack rolls, ability and skill checks. Your healing surge total and current amount drops by 3. You remain Exhausted until the end of your next short rest, after which you become Fatigued instead.
Fatigued*: You cannot Run or Charge, and suffer a -1 penalty to your Fortitude, and all Strength and Constitution based attack rolls, ability and skill checks. Your healing surge total and current amount drops by 1. You remain Fatigued until the end of your next extended rest. If you are exposed to another effect that would fatigue you, you become Exhausted instead.
Harried: You are totally surrounded by enemies (every adjacent square to you is occupied). As a result, you suffer a -2 penalty to your attack rolls, as well as granting combat advantage to those that flank you.
Nauseated*: You are retching and vomiting, and as well as granting combat advantage, can only take a single move action on your turn.
Shaken*: You are disturbed by something frightening, and suffer a -2 penalty to your Will defence, attack rolls, skill and ability checks and to saving throws.
Sickened*: You are repulsed and made nauseous by something, and suffer a -2 penalty to your Fortitude defence, attack rolls, skill and ability checks and to saving throws.