The best part of a performance is that you can do all that without switching modes, like on the helix, QC, or TMP. These other units give you good versatility within presets, but when you do need to switch presets, force you to hit a mode switch, switch presets, then hit the mode switch again to get back to stomps/scenes; a total pain between songs if you use multiple presets live. With Kemper, even if you need a performance for each song, a simple bank up or down gets you there. Even one rig within a performance, gives you a robust amount of versatility with morph and four toggles. But a performance beats the competitions single presets, which is the true relevant comparison, since changing presets mid song song is impractical and even impossible for the units with a big audio gap. Besides, you can get to another performance on a Kemper easier than changing presets on the QC or helix and without a gap (if you’re not already in preset mode)
The TMP is the exception here since you can switch presets without gaps, but again you’d have to switch back and forth between modes to get as much versatility as a single Kemper performance. And all three competitor’s grid layout leave you with no ability to lock things.
A workaround for your point 2 would be to get an external switch and set it to globally a control a couple modules. Set the display type on your stage to show the active status of the 8 modules and you won’t miss the leds on the external switch.
The biggest improvement the Kemper could make for rig and performance versatility would be to add an second locking option, locking just the effect and its parameters in a module, but not its active status. Then you could tweak effects you want to be in every live rig once, while having them only active by default in some rigs (the same way people utilize real pedals in audio loops)