I was at BG last night and was talking with a few people about ideas for this years megabattle. We mostly discussed the fear people seem to have about the super heavies.
The sides will surely be even when it comes to things of epic nature and as people have already mentioned, they can be felled by conventional anti tank weapons.
Something we did talk about, which Mike Do brought up last year but we ignored because he is short, was forcing superheavies to start on the table unless their rules force otherwise (trigons, daemons, thunderhawks, that stupid tau costs-more-than-most-used-cars-flyer). So all titans, baneblades, ig super heavies, brass scorpions, plague towers... etc have to eat a vollies of fire from turn one, makes them a bit more "reallistic" in how they would be manouvered in the 40k universe and remove their ability to *ahem* flank march to epic ridiculous proportions.
So here I propose, as a seemingly unanimously supported idea, having all superheavies start on the table unless their rules specify otherwise as a house rule for the annual megabattle.