I am fairly new to DDO, but not new to MMO's in general, and certainly not a newb to PnP D&D (and no, I didn't read through the entire thread, so don't hate if any of this has alreday been addressed).
One thing I'd like to see is an enlargement of the weapon selection.
Most notably, Polearms, and non-rigid weapons (i.e. spiked chain, flail, etc.). The additional range to attack with a polearm would add a nice dimension for both players and NPCs, and to overall tactics.
The addition of the Mattock would be nice (2H Pierce weapon that is non-polearm could porbably be put in faster than a polearm). 1d10ish Damage with the x4 multiplier in exchange for an Exotic WP feat.
Additional weapon mechanics that come along with certain weapons would be sweet. Things like hooked shaped weapons added to trip, non-rigid weapons added to disarms (that would also be a nice addition BTW) etc.
Oh and for halflings, Sling anyone?
On a grander scale, please please please please, implement the crafting feats. You already have tons of collectables and gems that would be perfect for special ingredients, and the gold is already there. PnP rules apply for costs, and what you can imbue; however, instead of making an item take X days to make based on a cost though, make the creation instant, and the CD on that creation feat = to the time it would have taken in PnP rules to make the item (that would seem more efficient since you already have the CD coding in game). I know it will take alot to add that in, but it would really set this game into a whole new level of awesomest D&D game ever.