That looks pretty sound to me. The only area that could be troublesome is where your filter pad sits on top of your mech sponge blocks. To me, that is a key area in that set up.
If you remove and clean/replace that filter pad regularly then that's great. If you leave it too long then the build up of crud on top of it may result in your flow being restricted, which can be very bad. Water will flow around it and maybe lead to unfiltered water going straight into your mech sponge blocks. You don't really want those sponge blocks gunking up because you risk eventual flow restrictions again.
Keep on top of your maintanance regarding that filter pad and you should be fine.