my sump, could i improve it

[TrailFish]

I agree with the skimmer comment. Get one. Based on your diagram you don't really have room for a skimmer in your sump layout (you could always get a hang on, or one that operates outside the sump $$!). If you did want a skimmer for your sump, most operate best at a specified fixed waterdepth, so you might want to get rid of the last couple of baffles and set on overflow before the return to the appropriate depth.

Also, as far as the turned down intake, I agree that the pump shouldn't be a vacuum but but I don't thing it will make a huge difference (alot of people put in a strainer to protect the pump which is even more restrictive to the intake). In any event, if the water depth is sufficient, you don't really need it. However, it can be useful to prevent air being sucked into the pump if the intake is not sufficiently below the water surface.

Just my 2 cents. Good luck with your project. Have fun.