SIPP drawdown

Adding the SIPP for UK based customers is a great new account option, after the ISA. Would like to request to add the drawdown capability sometime in the future. For example, when somebody hits pension age in the UK, to withdraw a certain percentage as cash (up to 25%) and then be able to withdraw the rest via flex-access drawdown or some similar mechanism. Would be good to make the SIPP more well-rounded. Thanks