In 7th, you could just throw a unit with great weapons at it, and have a reasonable chance of success. Or a Stone Thrower, which could do D6 wounds on a hit, wounding on 2s. Or a Bolt Thrower, which could Wound on a 4+, D3 wounds. Now, all of those options are wounding on 6s, meaning most things are useless against it, except for magic which ignores toughness, and very rare combinations (like HKB) which can insta-kill the STank.you think it's bad now?
Try facing them under 7th ed rules, no magic works and wounding capped out after so much so it was occasioanlly impossible to wound it.
Nowadays you always wound on 6's and it's magically defences have been shattered. Throwing anything that's "tiny strength - no save" is an option. Don't know the WoC magic well enough to know if they have that though.
Warhounds + poison might be a nice cheap option, it'll get it's monster save though
It just seems like a silly change to me, put in for the hell of it. Now, it can walk around freely, unless an opponent has a specific counter, when it simply dies instantly.