Yea I can see Cue Only is a big limitation here, particularly stopping you overlaying operations since "all data is recorded in all cues" (or at least that's how the desk plays them back regardless of how the information is represented in the internal datastructure) - so you lose the ability of another cue taking control over a parameter.
I came to FLX from Fat Frog. On Fat Frog the few times I used Partial mode I ran back to Full mode because I lost control of what Partial was doing. I've not had the same experience with FLX. I'm always in Tracking On mode and never have I felt the need or even the inclination to go to Cue Only mode. Compared to really advanced users, I don't do anything "that fancy" although I do have a reasonable number of LED and mover fixtures (although surprisingly on my last show, conventional fixtures did outnumber LEDs 2:1 which was unusual, usually it's closer to 1:1).
So, even as a "low-to-medium complexity" user myself, I'd encourage you away from Cue Only to Tracking. It really isn't at all scary, and SmartTag pretty much makes Tracking work the same way as Cue Only for 95% of cases and move on dark works beautifully in the background [1]. It's only when you want some finer grained control (or Remove!) do you need to start fiddling with SmartTag in my experience (which is theatre). I've had my FLX since 2015, so have done quite a few shows with it.
Go on, you know you want to!
Kevin
[1] Tip: Programme a blackout with "1 THRU @ ."