Koeman would be a great manager to build the foundations of this new start under Moshiri. People call him safe but more than anything he's adaptable, seems to be a very good coach and has a fairly consistent record in the transfer market. A wise head who can gain the trust and respect of this group of players is vital, especially as many could very easily become disillusioned with the seemingly inevitable loss of Lukaku/Stones.
Said this previously but De Boer has been panned by the few Dutch mates I've spoken to over the last few weeks, his football is seemingly dour and he's struggled majorly to bring on some of their better young players (Fischer etc.).
Sometimes the sensible choice is the right one.