Is your current fluid trainer a kurt kinetic? You could get the inride sensor for it and poof, you've got a (mostly) bluetooth smart power meter you can pair with the iphone and run zwift.
My current setup is favero assioma pedals, any of a couple dumb trainers, an old gaming pc I bought on craigslist for $150, and a cheap $60 amazon projector so I have a 9 foot zwift screen in front of me. The only negative is it needs to be somewhat dark in there, but that just adds to the "pain cave" element.
How does that work for you in terms of zwift power / realism / cheating or whatever it's call.
I have the same setup like you (dumb trainer, power meter) but have not tried zwift as it needs real $ (even tho there is like 7 days free trial but I didn't take it up yet).
In all honesty, I want zwift for the racing aspect of it. For structured training, I've been using EgrDB workouts and putting them into GoldenCheetah. Works for me.
Would having a dumb trainer NOT make it so "real" so to speak?