A UK bomber+fighter+cruiser+destroyer versus an Italian battleship+2 cruisers is about a 55% UK win (netting a transport as well) and 65% to kill just the warships…
Our group noticed this too.
…The only problem with option a is that it fails 25% of the time. Not a brilliant prospect, especially if you are better than your opponent, and hope to grind out a long and sure win.
But we concluded the probability of actually losing the fleet in this case is only 15.125 per cent (65% x 25%). Although I am new to A&A:50, my experience with A&A games is that playing too cautiously can be folly. Sometimes you have to give your opponent a fifteen per cent chance for a lucky break - often a much better chance than that. If you wait only for plays with more than an 85 per cant success rate, you’re probably never going to grind anything out. It would be like playing Texas Hold 'em and waiting for pocket aces.
Furthermore, if you are so much better than your opponent that you don’t even want to give them a 15 per cent shot, you can probably win even if they do sink the Mediterranean fleet (should they even make that play).
That said, although I think 84.875 per cent is enough to make option a sound, a higher probability would of course be better. Italian fleet aside, I’m not sure how much worse attacking sea zone twelve is versus your next best option. Basically, I recommend you attack Egypt no matter what, but that you don’t sacrifice much for sea zone twelve. If you think sea zone twelve is almost as good a target as sea zones two or nine anyway, go for it!