Hello there. As work continues on my zine, I thought I would post some more monster tips. I realize not everyone really wants to go back and edit old monsters in detail to bring them up to the errata (and they are still too weak even then), so I thought I would share some easy tips to help use pre-MM3 monsters with the least amount of work. You can do these on the fly with no need to make notes or edits. This should work pretty well up until very high levels, where you won't be able to get away with it as easily, and you'll need more damage.
1. Add 1/2 their level to the damage rolls. Simple.
2. Double check the attack bonuses and adjust them if needed. Easy thing to fix. Use their Level + 5 vs AC and Level +3 vs NADs.
3. Lower the recharge number of powers by one. So a recharge 5 power becomes a recharge 4. Encounter powers change to recharge on a 6. Easy to remember.
4. Give the monsters a "Double Attack". Give creatures a single Standard Action that allows them to make two RBAs and/or MBAs. This dramatically increases accuracy obviously, and that is a balance vs the weaker damage. So if you see a Basic Attack, just tell yourself you can also make it twice. Pretty simple. You may want to designate a ranged At-Will as a Basic Attack on some older monsters.
5. If they still look too weak, or don't play tough enough, let them Free Action attack when they are bloodied and/or when they die.
There you go, nice and easy. It's not perfect, but it's quick, you don't need to consult errata, and the monsters now are worth something.
I often use some of these tweaks on even 'updated' monsters, and I would recommend you do the same, especially giving them Double Attacks and lowering the recharge numbers.
As I mentioned earlier, both these and my 'Savage' monsters work best from Heroic to about 15th level. from there you likely need to pile on some auto-damage, even if you have updated the damage expressions.