you can use the FM3 with 2 additional "simple" external switches and an expression pedal (or 4 switches if you don't use an expression).
those external switches can be set to do anything the built-in switches can do. but you can also use them simply to change Layouts or Views which change what the on-board FM3 switches do. this is just like changing to Preset Mode, Looper Mode, etc on the AX8.
when i have a simple gig without looping, i use just the 3 on-board switches in 1 Layout and View. that's 6 functions with the 3 switches with tap and hold functions. further, one function can be a "Scene Toggle" giving me 2 Scenes per switch. put another one on the Hold function of the same switch and i now have 4 Scenes with 1 switch (with a bit of "priority" in how you change to all 4 scenes). then i put 2 different effect on/off on switch 2, and Tap and Tuner on the 3rd.
when i need to loop, i plug in 2 external switches. the left external does Tap and Tune, which frees up that 3rd switch described above. the right external switch changes between 2 Views (or Layouts) so it becomes a Toggle. View 1 is what i described above. View 2 is Looper Rec Play and Once, with Scene 1/2 Toggle as a Hold on the Once switch.
that right there gets me through any gig with 4 Scenes. much better workflow i think vs the AX8, since i can now change Scenes on the Looper View, which you couldn't do on the AX8.
i've also experimented with adding Scene Toggles on the External instead, giving me up to all 8 Scenes there if needed (4 per switch) leaving the on-board for other things like more effect on/off or channel selections.
just those 5 switches give me so much control over things without diving through modes/Layouts/Views.
i'll have a video soon with Definitions, Default Layouts, Custom Layouts and more soon. it's all really simple once you understand what each thing does. then you just choose what you need and put it there.
3 or 5 switches compared to 11 of the AX8 are way more powerful and sometimes less confusing. it all depends on how you set it up.
on really involved gigs, i'll bring the FC6 for even more switches, but that's been rare.