I would like to strongly suggest to bring back the win+space shortcut! It has never worked badly for me, for for me there was no valid reason for removing it. Furthermore, ctrl+alt+space is a pain to press. Just try it, the win-key is between the ctrl and alt. Ctrl+alt+space is very difficult to press without using your thumb. With the use of your thumb, you need to put your hand in an akward position. And all along the chance of accidentally pressing the win-key.
Win+space is MUCH MORE easy to press, by pinky+index finger.