I'm not against adding features to make PvP more fun. But I think you have to be a little more realistic; "comparable or superior" is not going to happen, even if we allow 50-team battles or allow rogues to sneak and cut fortification in barrooms. PvP in DDO will continue to suck.
"Superior" PvP requires, IMO, some basics:
<1> High HP to DPS ratio, so players live long enough to make strategic choices. DDO's small HP pool and limited SP makes combat too rush and dump. Our DPS is geared to massive numbers of enemies with vastly more HPs than us, so reducing that DPS to "sensible PvP levels" will gimp PvE.
<2> A complex dynamic allowing all classes to counter other classes, leaving none out. DDO's PvP disadvantages most non-casters except AA Rangers. Rangers, Paladins, and Rogues are especially crippled by the lack of good PvP abilities (unless the Ranger takes F.E. in player races, or players become E.O., &c.).
<3> An intricate reward system that makes PvP profitable. DDO isn't geared to make PvP more important than PvE, which means its PvP will suffer. Period. In Shadowbane and other MMOs I've passingly flirted with, your guild targeted regions on the map to gather wealth and resources to craft powerful weapons no-one else could; or receive titles and gear with special l33t properties. Those devices guarantee that (a) there are people beyond gankers willing to PvP, and (b) there is rhythm to the PvP madness.
Judging by the framework DDO has, it will not have even "comparable" PvP even with a few minor tweaks. It will only have "comparable" PvP with a pretty major overhaul -- too much overhaul, IMO.
Best idea to integrate PvP beyond the barroom brawl is to just design a quest that allows two teams. Storming a castle to retrieve an artifact or something. You can marble PvE questing with optional PvP, everyone contributes towards quest completion even if they belong to a "bad at PvP" class. Pop a couple chests with normal per-level loot tables, and call it a day. It won't even be "comparable" to other MMO's for PvP -- but DDO is a different kind of MMO, and doesn't need to worry about those kinds of comparisons.