I think it would be better to have everything working fine in portrait
mode because its a pain use the phone in landscape with one hand.
there are situations where you cant use/hold your phone with both hands.

what can be done:
1.lock/filx the search bar in apps like contacts so you can use it in portait mode and
you dont have to slide ou the keyboard when you want to search.
2.A new system virtual keyboard that works in portrait mode
and landscape mode.
3.make all applications work in portrait mode.