From what I've read it's not an easy option and really needs careful consideration but I don't think that bariatric surgery for type 2 'remission' is necessarily simply about losing weight
There is an interesting paper that looks at the possible mechanisms.
Mechanism of Metabolic Advantages After Bariatric Surgery
It’s all gastrointestinal factors versus it’s all food restriction
Filip K. Knop, MD, PHD and Roy Taylor, MD http://care.diabetesjournals.org/content/36/Supplement_2/S287.full
With at least one form of bariatric surgery (Roux-en-Y gastric bypass) is that type 2 remission (41% with strict criteria, 80% in another trial with perhaps less strict criteria) occurs
before weight loss. One recent study using this type of surgery with people who had lower BMIs than are normally operated on ( <35) achieved remission in 58/66 (87%) of people who had had diabetes for a median 9 years and none of these reverted to diabetes in follow up over a median of 5 years.
In the case of this type of surgery, a strong case has been made that 'surgically induced direct delivery of nutrients to the small intestine increases the GLP-1 response to a meal and also increases other hormones which reduce appetite'
This GLP-1 response is greatly diminished in pre diabetes and Type 2
It may be that higher levels of this incretin following surgery are responsible for the immediate reduction in hyperglycaemia.
(There are drugs such as Victoza which mimic these incretins and are used as a medication in type 2 diabetes)
https://en.wikipedia.org/wiki/Glucagon-like_peptide-1
But both before and following surgery there is also an immediate huge reduction in calories. It could be that this negative calorie input is also an important mechanism in the remission This is what Professor Taylor has sought to mimic with the 'Newcastle' 600 cal diet.
(but no long term results or full trial yet )