Back in my classic playthrough, I got a strong impression that all wands with critical chance modifier seemed to almost disappear altogether. It was impossible to find two wands with +10% critical chance. All the ones that had +5% were only blue-tier. Legendary and divine-tier ones pretty much stopped being spawned with critical chance.
But then a big problem with Act 4 is that it is really hard to outfit your entire party with decent equipment. There are only a few traders that do sell equipment, but they don't sell equipment of all classes (STR, FIN, INT), and sometimes they don't even generate magical items. You're at level 19 and you realize your mage is still using level 17 pants, and want to get a new pair of mage pants with decent modifiers? Good luck with that.
I just hit level 20 earlier and realized my mage is still using level 17 and level 15 wands.