Actually no. German trains are often late, true, but outside of that its actually very nice. There are a lots of lines and lots of collections. The only time its a bad idea is if you have a real time constraints.

But the problem is: everybody doing a trip with a transfer has real-time constraints.

With Interrail, that is doable. You’ll have to mostly plan for overnight stays in large cities, but that’s what most Interrail users want to, anyways.