I think they thought it would be too confusing, and they wanted to keep the focus on Thor and Jane. Since there was nothing but friendship between Thor and Sif in the first movie, I hope it won't look strange that she has feelings beyond friendship in the sequel all of a sudden now.
Cool! Thanks for posting this here! "She is very much in love"... that sounds great!!
That glance of Sif (at Jane?) in the trailer was so great mwhaha.
I must admit despite my username I never cared much enough for the Sif in the comics. She was not giving much for Midgard and was always too arrogant. I took the name just because I do love Thor and cause she is a female asgardian warrior. Jamie's Sif is so much beyond that. I absolutely love her character in the movies. She's truly leveled up that character and now I am so glad, I didn't pick "Enchantress" as my username.