My system actually has more control modules than anything
else. But that's me...I find the most limting thing about non
modular synths is the inability to create control voltage streams.
ALong with your ADSRs, may I suggest a trigger modifier and a
fixed voltage source (A-165 and 176). For about $75 total, these
two will allow you to use your ADSRs as LFOs as it is quite easy
to make your ASDR self oscillate with those two and they will
come in handy for other things as well.
hope this helps,
Peter