It seems to me that the slopes of the envelopes are more or less linear. It would be great to switch to exponential or logarithmic envelopes in addition, which is quite important to get some of the classic sounds right and it shapes the sound definitely different then linear slopes do.
Yes ... there is the trick of recursive modulation, as described in "Tips & Tricks", but this costs us for every section of an ADSR generator at least one or up to three of the precious user assignable destinations.
To have both options would be a great asset for every sound-designer
Edit: The option of linear/exponential envelopes should be stored with each patch seperately.