I guess how one feels about where the keys are depends on perspective… coming from the Mac side of things, I always make sure the Alt/Cmd key is the command key, and there’s usually one on each side
But… in talking about a PC keyboard, I can say Alt sits in the same position and afaik, there’s also usually two of them (one on the left and right side of the spacebar… although some international PC keyboards have the AltGr key there), and imho my theory is this could be why the Be designers chose it; if one looks at where command sat on a Power Mac (or clone) back in the day and where Alt sits for the Intel releases, it’d almost make sense. But who knows? It’s just a theory and might just be sheer coincidence because I still have to flip option and command over every time. But anyways… first solution is maybe leaving Alt as the default system key to help solve this?
The second is would the Super (i.e. Windows, ‘start’, or ‘meta’) key work? I know most PC keyboards (on laptops at least) only have the left side one, but on large keyboards, I have spotted two before – so that might be an alternative? It’d probably be awkward though since that’s usually right smack in the middle of Ctrl and Alt (or further over if there’s a function shift (fn) key, as you mentioned). Otherwise, I don’t know what can be done about your dilemma with the control (Ctrl) key, honestly… that same struggle would be faced by those running ReactOS, QNX, KDE, Gnome, etc. since they default to all main shortcuts using this key. Wish I could think of something more… but there’s only a few major modifiers by the spacebar to pick from. And I can see where getting used to Ctrl 90% of the time then needing to make the correction to another key every time (if you left Alt enabled or switched to Super) on a Haiku box would be annoying; mainly because I do this in reverse whenever I’m on a Linux box, etc… I have to remember I can’t reach for Cmd and know the feeling.
Also… on the left-handed OS topic, I guess the thing I’ve always thought about (both on Haiku and the Mac) is the position of the cursor… especially on BeOS because it’s an actual hand always pointing the wrong way It’d be nice if the hand could flip to either direction with a radio button or check box in Input or something. Hey guys… maybe a feature for beta3? But… I guess the right glove has been a part of the OS since the '90s, so… oh well
Crazy part is I always use mice with the default buttons (right button under my index finger) even though I could reassign the numbers in Mouse (now Input in Beta2) Mainly because every computer with a mouse I sit at that’s not mine I usually swap hands with and it makes life easier to use mice as is.