Remove/Replace Fortification.

[Angelus_dead]

Currently, a lot of monsters have too much HP, too little AC, and either attack bonuses that are much too low or much too high

Often a lot of players with a D&D background wrongly complain that monster hp in computer games are too high, when really that is a necessary artifact of the conversion to a realtime multiplayer system. But DDO has often taken it too far in some recent content, such as with many of the humans around Dreaming Dark or the efreeti in Demon's Den.

(The earth elementals in Acid Wit are an interesting divergence from typical DDO monster stats, but the retain the problem of all earth eles: wasting their time Earthgrabbing someone who is immune)

Another aspect that needs to be considered is that of exclusive buffs (bard buffs mostly) that make balancing incredibly difficult since the difference between having the exclusive buffs and not is so huge (9 damage, 7 attack, 4 AC, etc...). Almost every non-bard-exclusive buff can be replicated to a lesser degree by another class

You're leaving out the Paladin aura buff... and the light monk finishers, but those have less magnitude.

Long ago when the big list of future prestige enhancements was released, I suggested that many of them could be given lesser versions of class-specific buffs to help smooth out the difference between having that character or not.

It went something like this:
Knight of the Chalice- Inspire Courage damage
Purple Dragon Knight- Inspire Courage damage+hit, Aura AC
Shintao- Aura Saves
Henshin- Barkskin
Warpriest- Haste

In addition, what should be done is to relabel the Inspire Heroics AC bonus from "Dodge" to "Morale" (or something), and then create a few new abilities that provide that +1 to +3 Morale AC. Might not be bad to also give bard-like buffs to some cleric and FVS specialties while we're at it.

Note that the non-bard versions of Inspire Courage would tend to be lower in uses, duration, and targets, meaning that not only would they provide smaller bonuses than a real bard, but they also wouldn't be guaranteed to be up for 100% of the combat in a dungeon. For example, the KOTC might spend a Smite to give Inspire damage for 30 seconds at a time, making it a boss-only bonus (which is when you need it most).

It is interesting to see how Warcraft is de-exclusivizing buffs in their next expansion. They just gave Mages a copy of the powerful Shaman Bloodlust.

while remaining fairly free from danger because someone else has aggro.

Yes, the devs should try harder to make monsters swing at whatever opponent is blocking their movement, which is what happens automatically with player characters. If you target a monster and chase him around swinging, you'll inadvertently hit whatever other monsters get in the way. It would look goofy to have monsters start doing their attack animation when they don't have anything in reach, but that can be dealt with.