From what I read, the touch bar is a separate system, with its own processor and running watchOS - effectively a remote display - so an app crash shouldn't affect it.

I would certainly guess that the OS gets pre-emptive access to it in much the same way as it can trap system key interrupts before they go to applications, but I'm still wary until there's a lot more information available on this. Another case is what if the app decides to replace the ESC key altogether? If that's prohibited somehow then what's the advantage of removing the physical key?

TBH, a separate OS sounds like one more thing to go wrong, which is also worse, not reassuring. I'm also not keen on the idea of someone remotely rooting my touch bar - also not a problem I currently have to worry about.

Just read the Ars review - it looks like the bar is divided into three, with only the middle area fully under app control (the left hand area showing dialogue box controls or escape). It does say that the bar slows down under heavy load though.

Hm, so what happens when an application locks up with a dialog open? Sounds like you may need to CMD+TAB first to get the ESC key back, which is at best going to be a nuisance (and I'm not sure exactly which OSX shortcuts are non-maskable in the way that CTRL+ALT+DEL is in Windows).

Sure, but there is a whole separate piece of newish software (watchOS? touchBarOS?) that Apple will no doubt develop, enhance and update regularly. It is perfectly capable of having its own crashes and issues.

> the squashed arrow keys are as much of a problem for me as the missing escape key

Could you elaborate on this aside? To me, it looks like a strict improvement on the arrow keys since the up/down keys are identical and the left/right keys have simply been embiggened (stretched upwards). Or do you think the negative space above the left/right keys gave important touch feedback?

Yes, the inverted T arrangement makes it a lot easier to rest your fingers, or quickly find the correct key without looking when moving between the cursors and the other keys/touchpad.

The keys are already big enough, so it's not a strict improvement and even if bigger keys are better, why are the up/down ones less important than left/right? If anything I use up/down more, because I use them for both reading and writing, whereas left/right are almost exclusively for writing (would be more so were it not for the lack of consistent PgUp/PgDn shortcuts on OSX: these are sometimes bound to left/right and sometimes to up/down depending on the application).

Having used both types of key arrangement (and others) on various cheapy Windows laptops, I know that for me at least, the inverted-T (without extra keys crammed into the spaces) is absolutely essential to being maximally productive at the text-related tasks I spend 95% my time doing. I can adapt to a 3/4 size keyboard more effectively than I can adapt to a full-size one without the inverted-T.