I don't think one, by itself, without the war altar is cheese. Nothing wrong with having a single heavy hitter, and every army has monster-slayers that can pose a real threat to a stank. It's balanced when you consider how pretty much every army (with few exceptions) can bring at least one large, ugly target to bear. Many can bring two or more, easily; even O&G can bring a Wyvern and Giant and split your heavy hitting cannons.
One stank AND a war altar, now you're approaching cheesy. The war altar is a steal points-wise, and a tank forces people to split their attention, but that's the way it is sometimes. When you bring two stanks AND the altar, you're really pushing the cheese envelope.
Personally, I think it's tough for us to have a cheesy army at all (we're awfully balanced and have a lack of uber-killy units), but the two stank and altar combo is about as close to it as we get. That, or (arguably) a gun line.
One stank alone is, to me, no more cheesy than any heavy hitter on its own, and has its vulnerabilities. Should we get rid of it? Well, I'm not a huge fan of it, and ordinarily never take it, but I think if we dropped it we should get something heavy to replace it, for the sake of balance. Love the stank or hate it, it serves a purpose in tourney lists and competitive play.