That would be absolutely brilliant! Especially for easy parallel compression and the like.
Maybe also a great idea for switching devices on and off (which can’t be automated right now)
Pattern Commands are also a form of automation…
I really miss this feature. 
Maybe we could just have a “dry wet” slider built into every effect container in renoise rack? Just make it hidden by default but can be revealed/activated by clicking on specific icon.
Been suggested before. I believe one of the biggest arguments against it by the Devs was the 15 parameter limit for having everything accessible via Pattern Commands. Now we have alphanumeric Pattern Commands, giving access to 35 (plus On/Off) hopefully they will be willing to reconsider 
Just right click on the bypass button of the effect , this will insert the command in the pattern editor
Absolutely but, as explained in the thread below, there are some “problems” with this when using the new Alias feature for example.
That’s right, I should have mentioned I want to trigger them through MIDI
I didn’t knew that. I always hand-coded on/off’s 
I am in favour of the initial suggestion: a meta-device for dry/wet. It should work for 3rd party VSTs also.
just get a send track or two and get yourself a hydra, don’t be so lazy
You are missing the point 
if you have nothing constructive to say please spare us such comments
Pfft… Send tracks and Hydra, DON’T BE LAZY.
Real men (and Amazon women) don’t use stinking send tracks and hydras. They render dry and wet version and combine them with a hex editor.
Please show me how this works.
We just need racks similar to Ableton’s.
I’m actually a tiny bit for this now. The only things missing proper dry/wet control are Scream Filter and the 2 Compressors, though.
Certain plugins report inaccurate delay times that cause phasing issues despite Renoise’s very solid PDC.
A dry/wet metadevice with a built-in (positive only) ms/sample delay control for the dry output could allow you to ‘tune out’ the phasing. Meaning you could quite easily do proper parallel compression with any compressor VST you like.
On a related topic, it would be nice if all native effects had consistent (the same) dry/wet settings. For bonus points, make them use the same pattern command.
Yup, I mean we’re almost there just look at it. Probably way easier to implement than some fancy modular thing.
My last project had about 15 sends before it became too much of a chore and I abandoned it.
Renoise, to me, is all about being simple but sounding complex. I hate reversing that workflow to do a simple parallel effect in a convoluted way.