I guess after DTC , ELSS will not exist. because ELSS will not come under tax saving scheme.They simply convert ELSS into one of the equity diversified fund. in such scenario people sell and buy MFs unit on the same day without any cost. So u can get the new NAV purchase date and new capital. After some year if u sell , LCGT will be calculated from the new purchase amount.
So i guess it will not impact much