If you IMDB the 2nd episode, Rose, Jackie, Jack and Sarah Jane and the "new" Doctor are all listed.
I just checked the cast list for epi 1 and Jack was listed but none of the others were....hmmmm
Having Jack in it (for me) would make the regeneration easier for me. I was almost in tears in that seen in the Cafe when he was looking at Donna
Im gonna give the new guy a chance....but Tennant is "my" doctor and things are never going to be the same.
I do think Simms did an awesome job in his part, and the cliffhanger, while I dont really understand it has totally blown Dave away