Two seperate points, firstly I like my toast grilled but only on one side, try it. You will be pleasently surprised.
Secondly i had anchovies on toast this morning, far superior to toms sardines.
If I'm making cheese on toast I generally lightly grill one side of the bread, then turn it over and put the cheese on the soft side. When I say put I mean completely cover, no bread should be showing for direct heat transfer.
If it's crap cheddar, then I'll often put a light scraping of english mustard under the cheese, helps bring out the flavour.