I think this needs to be considered in the light of probable risk, which is negligible.
There has in the last 20 years only been one take off accident at Luton, G-AVGW (HS 125) in 1967, on a training flight.
I cannot remember an accelerated stop which ended up anywhere near the far end of the runway, the only one I know of being the Aztec/One Eleven collison where stopping from the current Charlie intersection on a 08 take off was not marginal.
Therefore in my view an accident of any type is unlikely and the effect of an intersection vs full length departure is probably negligible.
On a recent departure form Luton in an Easy A319 on Rnwy26 form the Alpha intersection, we were airborne arround the Bravo intersection with around 600m remaining.
If we are talking margins this is far greater than I remember those availble to One Elevens to Monastir on hot summer days, or TriStars to Cyprus from the full length.
If the numbers are done and performance is OK intersection departures do not represent a signficantly higher risk, but do save time and fuel IMHO.