Well to be honest we should have invaded srilanka, Maldives and Bhutan back in the 70s. Their population density is lower.
Srilanka and Maldives would serve as excellent millitary ports and good tourism revenue.
Not to mention you also have the right to all the resources 100 kilometres off the shore which can include oil reserves.
With Maldives we would have a huge chunk of Indian Ocean under control and no Chinese occupied military ports.
Bhutan would have been hard as China wouldn't let us occupy it but we could have made something work.
Bangladesh and Myanmar have more problems then benefits, best to leave as it is.