The reason people advise routing several tracks to one reverb is mainly to do with CPU conservation, as you're aware, and to save having to match the controls for each one. Also to conjure the sense all the musicians are playing 'in' the same environment. I'm working with several voice tracks in a play and I want the characters to sound like they are in the same room together. As they move to different parts of the house or leave the house and go into the garden, or get into a car... etc.
But if you're dealing with electronic music, you certainly have the creative freedom to create somethng else entirely and the environment/atnosphere you might want to conjure can be abstract. That's not to say you can't do this with any kind of music. It just depends on what you want to do.
A lot of people like to add extra 'verb to their drums to shape them up and add presence. Maybe they want to creatively shape each part of the kit individually and once applied, you might not want the same for your guitar. You might want a keyboard sound to possess a distinctive decay... Sometimes, I find some instruments just need a little bit of individual toning and shaping, which I can't quite get with a single catch-all effect. VSTs do give you a lot of extra freedom and that's why so many people are moving over to computers, from old conventional gear.
I appreciate the need to save CPU but in practice, I've never had an issue when I've used many VSTs together. The time to worry is when a problem occurs.
As for reverb units conflicting, that would be the result of a creative analysis, rather than a technical one and certainly not one which needs to be governed by hard and fast rules. You say it sounds right... then it IS right.
DAW software manuals will make recommendations for managing CPU and memory but whether it becomes an issue would depend on the complexity of the piece you're creating. Instinct should tell you when you're in danger of over-doing things.
To be honest, I suspect there are many more powerful machines used in home studios than mine - and the only time I get CPU slow-down is when my anti-virus is doing scans. The one thing I do notice, however, is the project will take a lot longer to load when I've used a lot of VSTs but once loaded it performs smoothly. I don't think music is really that much of a challenge to a computer, as long as you're within spec and the software is well designed.
Don't get too hung up on the hard and fast rules of conventional wisdom but consider them sensible guidelines. There is, of course, a certain elegance in keeping things simple on the effects front but if things are working for you, then don't let it cast doubt on your creativity, just because it's 'not supposed to be that way'. Don't create issues when there aren't any. Just create music.
Hope this helps.
Dr. V
