I don't think things have changed much but the biggest reasons for failure era still probably lack of ability. commitment and the fear of live traffic. This won't necessarily come out at IANS or in the Sim but only when actual OJT has started. It is possible to some extent to BS your way through the initial phase. It is rumoured that one or two have made it through by sleeping with an instructor
OJT coaches might sometimes seem harsh - however don't forget. you are working on his/her Certificate of Competency and he/she may step in at any time and take over. If this happens too often you are heading for the chop. You are continually being assessed and your progress. or lack of it, will be discussed at least once a month by the OJT coaches and team Training Officer. The decision to terminate training will not be taken lightly. You will be briefed on your shortcomings, a change of OJT Coach, even of team. may be considered and tried before the dreaded day comes.
in case of failure, is there a pay compensation ?
Why should there be? You failed, not Eurocontrol.
As usual. read the Eurocontrol website for info on salaries and shift working hours