Note entry in Staff View has slowed down because in X1 you can no longer enter notes with the mouse in one hand and change note duration using the number pad with the other.
However, entering direct from the MIDI keyboard using step record (shift+R) has stayed the same BUT there is a bug (CWBRN 3863) which prevents entering series of more than three 8ths or shorter notes. That's not fixed yet but CW have suggested a workaround of going Edit/Preferences/Display and disabling 'show all times as SMTPE'. This seems to do the trick for now.