A few times in this thread I have suggested granting abilities that provide new sources of otherwise exclusive buffs; a bonus that can currently be provided by only one character class.
There are a few of these in DDO:
1. Bards provide a morale bonus to attack and damage (up to +7/+8, going up later)
2. Rangers provide a +5 natural armor bonus to AC. (Potions or Madstone provides a smaller bonus, and bring drawbacks)
3. Paladins provide an unnamed bonus to AC and saves (up to +5/+4), which might be labeled as an "OfGood" bonus type. (It will go up again at lev18 with Defender of Siberys)
Class features like that are enjoyable for the players who have them, but they create a game balance problem: there can be a big disparity between parties which have those buffs and which don't, and there's no way for a party lacking that class to even partially close the gap (applies less to Natural Armor than the other types).
Therefore, it would be helpful to allow other classes to provide the same type of bonus with reduced power: most likely with lesser magnitude, but also possibly with fewer targets or less duration. That way parties are still rewarded for bringing the primary class with the strongest buff, but they have an option to take some other character type and still get a lesser bonus.
It's important to remember that no class should not rely too heavily on these features to be valued in a group, and they need other abilities to make them "stack" with other characters bringing the same buff.
Summary of suggestions along those lines:
Purple Dragon Knight: Mass buff +2, +3, +4 morale bonus to attack/damage. (Non-warchanter bards have +2/+2, +4/+5, and +6/+6 at those levels)
Shintao Monk: Aura effect +1, +2, +3 OfGood bonus to AC/saves. (Non-Defender paladins have +2/+2, +4/+4, and +5/+4 at those levels)
Henshin Mystic: Mass buff +2, +3, +4 Natural Armor AC (along with other effect).
Stalwart Defender: Passive self-bonus +3, +4, +5 Natural Armor AC.
Additionally it wouldn't hurt to let PDK's mass-buff include a +1,+2,+3 OfGood bonus to AC (not saves), even though that's stretching the usual definition of what "OfGood" means.
PS. I made a ton of suggestions for continued bard features.