EverNightX: I know some people don't like armor in DOS2 but I think armor feels better than misses in D&D.
It's actually quite common that I've found armor to not be worth it in CRPGs.
The reasons, of course, depend on the game:
* Weight of armor. In many WRPGs, you can only carry a certain amount of weight, or you suffer penalties based on the amount of weight you're carrying. Hence, in some such games, including Wizardry 8 and many Elder Scrolls games, I end up not wearing the strongest available armor because of this. (In Wizardry 8, I'd much rather wear some Robes of Rejuvenation over the late-game plate armor you get, even for a front-liner.)
* Armor requires extra maintanence. Some WRPGs have armor lose durability when hit, and then there's cases like Might & Magic: World of Xeen where armor frequently breaks and has to be repaired (and in WoX there's also limited room for armor in your inventory). At this point, there's the question of whether it's worth it.
* Game penalizes you for wearing armor. You might move more slowly, especially a pain in a game like Morrowind or Oblivion. Your magic might be weaker, as seen in Oblivion and Final Fantasy 2. Or, as is the case in FF2, heavy armor might ruin your evasion; in FF2 this issue is so bad that it makes the difference between winning the battle without taking damage (if wearing no/light armor) and a party wipe (if wearing heavy armor).
* Armor often doesn't provide enough protection to be worth it. This is often the reason why, in JRPGs, I often ignore armor upgrades in favor of weapon upgrades, or better yet, new spells (in games where they're buyable). When combined with other aspects (WoX again; there are entire areas, including the starting town, where AC is completely useless), it becomes hard to justify the use of armor in the first place.
Also, the D&D AC mechanic, other than it not making sense that plate armor makes dodging easier, has the problem of not scaling. When levels get too high, attacks either (almost) always hit or (almost) always miss, with the in-between case being so small it's not going to happen unless the game is very finely balanced, and such balance is fragile. Just take a look at games like Pools of Darkness and BG2: Throne of Bhaal for examples of this. (Or WoX late game; in the Southern Sphinx, if your AC isn't incredibly high, it makes no difference.)