I think because there is some black in the bay, electrical and vacuum hoses, that the contrast of the blue isnt enough.
so maybe reduce the black, easy way and cheaper than replacing or cover all of the tired look hose and wire coverings could be to use stainless steel sheet to cover all except engine, fuse box, air intake. that would make the engine the focus so any colour would 'pop', custom box, or arc intake box and cool fuse box cover. the only other thing you would see is the strut brace and possibly use some venting on the stainless covers to keep things interesting and functional heat wise perhaps...
that would tidy it up, give it that custom show look, easy to maintain and nowhere near as expensive as colour coding or replacing a heap of other stuff... definitely have a wow factor when you open the bonnet... i'll shop it up and show u...