I have no expertise in this area however an in similar situation to you, retired, converted to pension phase, some minor non-concessional contributions from my spouse but have never been advised to change the trust deed in last 5 years.
Most of the trust deed appear to be generic statements made to comply with rules etc and covers a wide variety of explanatory issues so once established would remain in place unless there is an issue between trustees and they disagree on the running of the SMSF?