Felon said:
AC does exists...as Defense. Defense depends on bonuses from class and level as well as dexterity and armor, but they function in the same manner.
They both function as the DC to hit the character, but they are derived differently, which makes all the difference. It's quite possible that the class and level defense bonuses of characters in d20M necessitated either changing shield's bonus or increasing its level.
Then again, they could be public playtesting, but I doubt it. I'm not privy to their design meetings.
How are actions different? A "standard" actiion was renamed "attack" action, but again we're talking about superficial differences. There's no substantial difference in how actions work between D&D and D2M.
There are no partial actions in d20M, which necessitated rewriting haste (and is a pretty substantial difference, by my account).
(Notice also the change in bonus to defense, lower just like shield.)
As D2M is not really a game but rather a system, and that system happens to be the one that D&D is largely based off of, I'd be very surprised that they'd *not* try to achieve compatability between the spells of the same name presented in both sets of rulebooks.
Well, my book says "d20 Modern Roleplaying Game," not "d20 Modern System." Still, you're conjecture that it isn't a game could be correct.
You are correct, however, that there are 2 separate systems. Thus, why would they try to make them the same system, or compatible, after the fact?
To answer your original question, I'll give you 20:1. But, you could be right, after all, they are revising the core books.
