I just don't see Matt bringing the court savvy that Robert Horry brought....ever. Matt's not wired the same. Bonner can hustle and focus on rebounding, loose balls, playing physical, and knocking down open shots from the perimeter. He is what he is.
Horry could pass, slip screens and cut to the rim at the right time, he played the high-low to Tim very well, he rotated instinctively. Anticipation and experience were key factors to Rob's success defensively. Bonner has shown none of those qualities.
You can't replace what Rob did but Bonner can use what skills he has and he can PAY ATTENTION to what is going on out there. That would help.