I would start counting how many Rohingya's these pesky Bamar's have killed so far and go in and exterminate 10 Bamar's for each Roningya. Yes they are our kin and Arakan is their land as much as it is of Rakhines.
War and force is the only option with these subhuman beings. No one should get away with ethnic cleansing and genocide in this day and age.
BD is doing relatively well economicaly speaking so defence expenditure should be doubled(phased in over 5 years to minimise sudden shocks) and then in 10-15 years time, all should be well to retake Arakan.
Reasoning never gets anyone anywhere.
A focused BD can easily streamroller Mynamar.