I think I was being vague in my terminology. I wanted to say more broadly that German verbs are generally simpler than English ones because there are fewer tenses and aspects. There are however a greater number of strong verbs in German than in English.
I'm not familiar enough with German to evaluate. But when I think of Spanish, you've got 6 conjugations for every tense, and a whole bunch of different tenses. That makes for many dozens of different inflections, just for verbs.
English does have a rich ecosystem of compound verbs (https://en.wikipedia.org/wiki/Compound_verb), but if this is taken to be part of the complexity of English verbs, I don't know how this stacks up to other languages.
