Originally Posted by Dark Raven
Maybe they don't want to use Chen Lu because a) he's a villain again, and if they had a problem with Mandarin as a Chinese villain, then how are they going to suddenly accept Radioactive Man as a Chinese villain; and b) Edgar Wright is still probably not ready with Ant-Man for them to film any post credit scene with an Ant-Man actor confronting Chen Lu. Thinking Wright might be even remotely ready is wishful thinking.
"Dr. Wu" is not a villain at all. RorMachine over at That Other Website is getting confused and spreading mass disinfo about that; the actual Deadline article by Nikki (linked earlier) doesn't say anything at all about "Dr. Wu" being a villain; only that Wang Xuequi's role is not a huge part.
By all appearances in the photos, his role in the movie is just to perform some kind of surgery on Tony; and it's a safe bet that it's the surgery to implant Extremis in Stark.