The big problem with the GW system was the stun rule. If a character was stunned for an action or two, they couldn't do anything and the Judges would use this rule to drop the hardest perp imaginable.
Actions were dictated by Initiative. The average cit would have an I score, generally, under 20, giving them 2 actions per round (out of a possible 10 - and you can bet that all players would use EPs to put up Initiative and choose special abilities which gave them extra actions until they could act in every one of the 10 pphases in a combat round). The slightest hit would usually give 1 or 2 stuns, meaning the Judges would often have 10 actions to a perp's 2, hit him on the first action for a stun, and get to have another 9 actions whilst the perp had none...
So, if you had Judges who had gained a lot of experience, they would become unstoppable. There was a Special Ability calle Knock Out which players would always choose, which meant any hand to hand hit causing a stun would render thier opponent unconcious. Coupled with the overuse of Stumm gas, this made players way too powerful if you allowed them to live through 3 or 4 big campaigns. So, you had to write adventures in which the perps were unrealistically hard. The average pickpocket who you needed to escape would have to have an I score of over 50, and preferably a high Combat Skill to boot. Since I used those rules from, like, 1986 through to 2003, and played pretty much constantly (once a week - hey! This is my favourite game ever!) it became second nature for me to stat up a bunch of perps pretty much off the top of my head, which I knew wopuld be a realistic challange for my team of Judges.
The D20 version has many, many advantages, but as I said, the lack of armour degeneration is a major thing I dislike about D20. With GW rules, evey hit would strike a location - be it on a person or a robot or a vehicle, and if it did not penetrate the armour it would damage the armour. I liked the hit location rule much more than the D20 hit location rule because knee pads would protect the legs only, helmets the head etc... and Judges would worry if they suffered 3 or 4 head-shots which thier helmet had cushioned as the armour value of thier helmet would deteriorate - there seems to be no equivalent rule in the D20 version, just an Armour value of 6. I want to be able to have perps aim for he head and to be able to mash up the repirator or comm-link or something. This may well be possible, but as I am so unfamiliar with D20 (I always used Warhammer FRP for fantasy games, as well as being fond of Vampire the Masquerade and (especially) Paranoia -
I am just feeling ATM like a novice GM because I don't fully and completely know the rule set, despite having ALL the Dredd books and the Player's Guide, and I have read them all cover-to-cover at least twice each.
Maybe I am just daft