It depends on what you count as irregular.
It's common to count all strong verbs as irregular, but that doesn't mean that they are completely arbitrary (strong verbs are those where the stem changes in inflected forms). I think calling them "irregular" is actually part of that dumbing down that you mention because if they're irregular, you don't have to explain the ablaut classes then, which determine the vowel change in the stem. It's true that in Modern Standard German you can't directly see for every verb which class it is in, but often enough you can. And if you can't, you usually get one of two options. I'm sure if you already got 170 of them, you should be able to see a few patterns.
German has lots of strong verbs (Wiktionary has ~900 in the category, though I don't know if all of them are properly categorised), but far less verbs that are more irregular than just that vowel change. Also note that many of these are in fact just repetitions of the same root with different prefixes, and they all inflect the same way.
So in the end, I think it's less about the absolute number of irregular (or just strong) verbs, but more about recognising the patterns and making use of them.