I know for a fact that the xp penalty will be there...as the dev's constantly strive to give it a classic feel *hence the hybrid penalties being in now
That being said I don't know how much effort will be put into making items wearable for iksars....really looking back other then effects and raw AC value all but the BP and legs in kunark armor were basically useless, if i remember correctly the hate armor for iksars was better then the normal Indo that dropped, the stats were actually done right so they didnt have int on them and stuff, those stats coupled with Iksars ac bonus evens them out....
Normal Warrior Hate Breastplate-
http://everquest.allakhazam.com/db/item.html?item=5230
Iksar Warrior Hate Breastplate-
http://everquest.allakhazam.com/db/item.html?item=5230
Normal Warrior Hate boots -
http://everquest.allakhazam.com/db/item.html?item=1813
Iksar Warrior Hate Boots -
http://everquest.allakhazam.com/db/item.html?item=5252
As you can see EVERY piece of there hate armor has HPs on it to make up for the fact they wont get the 100hp off BP and LEGS from Cobalt armor..
That being said it does hinder you slightly as you lvl, but thats also why items like Lumberjack tunic and others are introduced during Kunark...edit= and the scale armor quest are there for lvln up also as the person above mentioned