I am not local, but, I am a regular user, a new runway that would cater for the bug smashers may help.
It appears to me that these crazy speed reductions is to accommodate the slowest aircraft in the sequence. i.e. if we have a metro, Bras or dash up front we have to reduce to accommodate for them.
If these aircraft had a parallel runway and a STAR that separated them from the jets, then maybe a bit of the problem would disappear?