Should be

if he's successful in making another dimension, i imagine it could go a little wrong and start interfering with other ones.
So Rose's alternate dimension could be forced open....which would be very interesting since the other-Doctor-clone and Rose are in there (cue the proper Doctor getting all emotional

or coming to terms with the fact that Rose has another life now

)
Plus there's all the Timelords..... [including the Doctor's mum :3]
*cackles and rubs hands in the background*
oh the possibilities! lol