It could be said that the management should shoulder some of the blame. However, it should be remembered that the response time pledge had been put in place some years previously. It was introduced as a measure of the effectiveness of the unit. The possible implication of such a pledge was discussed at the time, however the management always stood firmly behind the decisions of a captain who elected not to meet the target - and therein lay the safeguard. Hopefully this will now be reviewed - it's tragic that it apparently played a part in an accident of the worst kind.
As for the so-called "VFR" route to CLK - it cannot ever be sensible to put a VFR route over the highest ground in the area. However, as far as I can tell, this was not primarily a GFS management issue, the routes were "given" to the unit as a 'fait accomplis', prior to the opening of the new airport.
However, the pilot could have taken another route around Lantau. No-one forced him to attempt to go over the top of the hill and no-one could have criticised him had he tried the route, made a controlled abort / turnaround and either returned to base or asked ATC for another route.
Harsh as it may seem (I know how sensitive an issue this is) but correct and safe judgement was perhaps clouded (no pun intended) by other issues at many levels. Every pilot faces such difficulties from time to time and usually it is easier to say yes and get on with it - knowing when to say "no" is the difficult part. The one thing I try to remember is self preservation - whatever else happens, the pilot is always in the crash.