OK, lets see how smart you are

In the MUN I am organizing, one of the potential topics for the Security Council is
the Reformation of the Security Council.
Do you think it is realistic, why and most importantly how?
My conviction is:
it cannot be done. The security council would obviously not want an influx of members that would underpin the major states, so they would veto any resolution. Also, no other GA has the power to reform the SC apart from the SC itself. And suppose it could happen, would it be realistic, let alone efficient?
The countries of the SC have troops at their disposal to use for peacekeeping. Would other countries with no troops to offer be able to tell the others what to do with them, especially since they don't contribute in the SC? I know it is dominated by UK, US, Russia, China etc, but still, is there any other feasible formation??
So, what do u think internationals?