After playing for a while, I've noticed something. For every main "role" of a party member (tank, healer, DPS, Caster) their are at least two choices for a nonmulti-classing character (Tanks=Pally,Fighter/Healer=Favored Soul, Cleric/etc.) with the exception of trap monkey. A party NEEDS a rogue to do this so my sugestion is to create a new class that allow another option.
I have a rogue and it is a fun class to play and with the trapmaking and other fixes to the rogue class that are comming I expect it to become more useful then just a trap monkey. Just a couple classes that I can think of off the top of my head for this could be ninja (Complete Adventurer) or Spelltheif (Complete Adventurer). Each one of these would add the normal rogue trap monkey with different abilities that could help out in different ways. Ninja (if monks aren't too much like one already) I could see easily transfering over from pnp to DDO.
Again these are just my thoughts so don't feel the need to personally bash me.