I think the old shortcuts are more accessibility-friendly since they can be typed one-handed, while the large distance between the search and arrow keys makes it necessary to use two hands. 

This may not be an issue if there are workarounds such as customizable shortcuts or sticky keys for people who can't use two hands for typing.

there is no guarantee there is a usable right alt key.  many regions have an AltGr only which does not function as an alt key.  so it cannot be relied upon as an a11y solution.

at the very least it would be nice if this could be a flag.  People that have an external keyboard (a number that may be growing fast because chromebooks now how the potential to be primary computer) would like to use the alt-up/alt-down ctrl-alt-up/ctrl-alt-down in their editors, terminals, etc...

It's strange, but little things like this and not being able to use the numberpad for pageup/pagedown etc somehow make a huge difference in trying to move to  chromeos as primary computer.

we have a policy as well to favor the search/launcher key as our modifier in go/cros-hotkey

ovanieva@ is already considering the removal of those key remappings.

+andrewxu@ is likely to work on the implementation.

+kpschoedel@, +tbuckley@ and +abodenha@ if they know some history or reasons why we should keep them.

I know no reason not to remove these mappings.