Ok - decided to play the mission in hard mode right from the start.
Mission 1 - SM: Absolutely ok - last fight was tough - had to retreat a couple of times to my barracks to get GA's health back up. Other than that it is fine.
Mission 2 - Orks: A thing which could be improved here - you need to build up resources very carefully and prepare very carefully. Also you need to build another barrack at a stategic better place - this is where it is not so good... You should be able to disassemble waaghtowers and barracks - or at least - give the player the opportunity to choose the main orc barrack where boys come out while ordering units via the buttons on the bottom left side.
keep you posted...