That is a bit unfair... Diablo is a "old " game.. they made a patch two days after LOD was out, one month and a half later they made a second patch for lod.. and 3 months after that another one. in six months they patched it out at least 3 times -and one of those patches added considerable content (1.09), not counting several server fixes.
Altough they haven't spit the now mythical 1.10 ( and I believe they never will), blizzard still beat activision by far when it comes to patching speed and number.
And, IMHO, blizzard products still set the standard in terms of game stopping bugs . They can be hacked and unbalanced, but still I think i never had more than 25 crashes in 2.5 years playing online diablo. (and maybe only 2 or 3 while playing offline) and I never ever found a real game stoping bug on that tittle.