Let me ask you this: If the offered a peerless boss que function(yea just like WoW or whatever other "crappy" MMO has) do you think a large portion of the mid-line CC users would switch? Let's go one step further: What if the EC offered a battleground capture the flag type deal where 10 on 10(5 on 5, etc) teams could battle for some shiney trinket or title or something to make them all warm and fuzzy?
It's an interesting thought and might convince some. The way the client battles of the past were handled obviously didn't work, and it's not simply content alone, otherwise people would have switched for the original 3D/Third Dawn client just to get access to Ilsh. Somebody made a good argument that the KR should have been kept that that Stygian Abyss should have been KR only. That would have tempted many CC users. While that's simply content on the surface, I think Stygian Abyss would have been more of a lure than Ilshenar.
I think the biggest issue is stability and performance. If they can knock out the bugs that lead to the EC horror stories being posted, they could go a long way towards converting people. On top of that, if they do the graphics update right, a lot of CC users would probably switch just to see things in a higher resolution, since it would be using the existing graphics they are used to (plus some of the KR stuff).
It's all in the package they present. I play the CC. I have no reason to switch. That is it. I just don't have the need. I can already do everything in UO that can be done with my current client and graphics are not a big enough factor to relearn a game I have been playing for 12 yrs.
With the EC, it was apparently a group package since Warhammer, Camelot, and UO's EC all run on the same client software. If after Star Wars launches, BioWare came back and said they wanted to shift at least Camelot and UO over to HeroEngine, I think the incentive would be there for some CC users, because moving over to HeroEngine, besides being the engine/server software that BioWare wants to use from here on out, would allow for much easier content creation and better performance for players. That would involve a 3D conversion though, even if they tried to lock the camera with an isometric perspective. I hope they move Camelot over to HeroEngine though.
If UO was on HeroEngine right now, we'd probably have twice or three times as much content added in the last six months than we've had, even with the current staffing levels. Plus it would be easier to borrow artists from BioWare/EA proper since the pool of people who could readily contribute would be much larger.
I don't see Warhammer lasting through the end of the year or early next - besides all of the numerous problems they've had, there is now another company licensed to make a Warhammer MMO.