Thing is, that's a very risky move for what is a family park... Indeed, they did pull a rather daft marketing thing with the worst nightmare stuff, but that sorta stuff is probably just over the threshold of what the park could produce so that it doesn't completely scar children for life, like Alien Encounter seemed to do...
At Thorpe, that stuff would fit... But not at Towers... Just too much, whilst in it's current form, it does enough for a fair few of the target demographic, whilst not completely making it inaccessible to them as well...