The following suggestion is influenced by FM8's adsr envelope. I donated it, but I still think about how great the time functions were on it's adsr envelopes. And thanks by the way for this great go to synth.
Ability to enable disable a tempo sync function for "env_time".
If enabled, have the ability to set exact divsion of time such as 1/4, 3/16, 5/2, 7/8, etc.
If disabled, have the ability to set exact duration of time in seconds, milliseconds.