By general purpose I mean envelopes and LFOs that can control custom targets - i.e. oscillator functions, effect parameters, other lfo's speed, etc.

I was recently comparing zyn with access' venom synth - in terms of capabilities if only. While zyn has much more freedom in terms of wave shaping (yes, more so than the infamous venom), it is really a pity that envelopes and lfos are statically target to 3 parameters only - namely, pitch, volume and filter cutoff. This tends to force the creation of static sounds, or to use several adsynth waves with different delay to fake movement inside the sound. For such a big and complex instruments, I found it to be a great limitation.

So my proposal would be to have a number of lfos and envelopes (2 each seems to be the most common case) that can be bound to OSC parameter(s), in a similar way as the macro bindings. I think this would help create a whole new generation of sounds for what I still find (after 20 years of vst) to be the most rich synth out there.