Sir ,
You have got an excellent set of experience and qualification. Based on your experience you can claim entire exemption from the training or articleship requirements of icsi.
Additional c.s degree will help you in internal promotions and also in government recruitment.
For eg - recently the income tax co operative union bank in mumbai required branch heads which also required an additional qualification morely a professional qualification.
Since c.a or cwa wont provide you exemption from training c.s will be a good choice for you.
Also if you are interested in risk management qualification , an international course which is way better than c.a will be the financial risk management (f.r.m) program by garp (www.garp.org)
CS shall help you in compliance department and will forward your career in that aspect.