Brown Jenkin said:
The Changes to DR, Monster Stats, Spell lists, and Base Classes means that anything with monsters, PrCs, NPCs and magic and mundain items will need to be converted.
This is a point that many are bringing up. This perplexes me, as the announced changes should have little to no impact on most previous released Core Rule Books, Splat Books, or Adventure Modules.
CHANGES TO DR
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Based on the information currently released about the revised Damage Reduction, you should not have to alter existing modules to make use of the revised DR rules.
if we have a module with a Werebeast that has a DR 15/silver in a non-revised module, and we apply the revised DR rules, the stat would not need to be changed. The rules that govern how the DR is handled would change, which is transparent to the module. Instead of being able to hit the Werebeast with silver or a +1 or better weapon, a silver weapon would now be required.
CHANGES TO MONSTER STATS
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Changes to monster stats should have no impact on existing modules. The module will still work as is without modification of the monster stats. The monsters existing within the module, or within other monster manuals, should just be considered different versions of a similiar monster. They are not cookie cutter copies. Not changing the stats of a monster in a module would likely be preferable to changing the stats as the module was likely balanced with the original stats in mind.
CHANGES TO SPELL LISTS
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This should have a very minor impact on published NPCs. 1st I would like to point out that we have not heard of any spells being removed from the spell lists, the addition of spells to the list should not unbalance or break any existing NPCs, thus they should not require any modification.
BASE CLASSES
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This category has the most chance of impacting existing material. Based on the information provided, however, I believe that most modules and NPCs should require no modification to use. Modifications that have been mentioned so far (with the exception of the much maligned ranger) are in the form of expansion of skills and skill lists. This shouldn't require an NPC to be reworked for a module or encounter unless the DM has a real desire to add a few skills points.
As to the Ranger, modifications to existing NPC rangers should not be necessary as none of their abilities are likely to be invalidated or become too powerful. If the NPC is a threat under the current non-revised rules, it will still be a threat under the revised rules and shouldn't require any changes unless the DM requires it.
The Changes to Base Classes will have the most impact on existing Player Character in my opinion, who may want to rework the character if they are using one of the changed classes. This should not greatly affect qualifying for prestige classes, however. Unless they make a very large change to skill lists, the extra skill points to certain classes still won't allow you to bypass the maximum points you can assign to a certain skill, thus limiting the Prestige class to certain levels.
-Josh
[EDITED FOR SPELLING]