I’ve been playing with a Helix Stadium for a few days now and the implementation of the secondary functions for the Mode foot switches in particular is absolutely outstanding.
Firstly there is a dedicated button to change Modes. Anyone who has read any of my previous posts here knows that I think the way Mode switching on the QC is implemented is deeply flawed; anything that can be prone to error is NOT good for live use, and anything that requires a simultaneous combination of footswitch presses - as is required on the QC - is prone to error (eg, accidentally press the Preset Down f/s a fraction of a second before you press the Tuner f/s and before you know it you haven’t changed Modes, you’ve actually changed Preset halfway through a song).
The Mode switch on the Helix is standalone; no combination required. You have a simple A or B with each short press, and even better you can assign any of the potential functions to A or B
Factory preset is for the first press to activate Stomp A mode (yes, you can actually have 2 pages of Stomps, Stomp A and Stomp B), and for the second press to activate Preset Mode.
You can change this to replace either of those two with Stomp B or Snapshots (Line 6 equivalent of Scenes) or Song Transport (ie to control playback / cueing of your backing tracks within Showcase) or Combo (the Line 6 equivalent of Hybrid Mode)
Almost even better, is the way you can change what the Up / Down foot switches do in the user settings. On the QC the Up / Down switches ONLY change preset, and can’t be locked (which I wish they could - have you seen the guy who designed a 3D plastic collar for the Preset Down footswitch, to stop him accidentally pressing it by mistake?)
On the Helix Stadium, simultaneously pressing the Up / Down footswitches changes what it is you are changing up or down; Bank, Presets, Snapshots (ie Scenes), Songs (ie backing tracks) or Markers (flags within a song, such as an automatic change of Snapshot).
Honestly, it is the most seamless and intuitive experience - and it is PERFECTLY possible to implement this sort of functionality in the QC, and people have been asking for this for literally years.