Switching would probably be worth it for you if you're paying regular fees at Commerzbank. I know several people from my village who did exactly that, and they save a decent amount of money each year. With DKB you don't need a minimum deposit for the free checking account, and neither does ING - they've got really generous conditions. With ING it's basically so that the account is completely fee-free, and with DKB too, as long as you're getting money in regularly or making card transactions, but honestly you don't need much for that. My husband switched two years ago and didn't have any problems with it.
The only thing you should watch out for: take a look at what else is important to you. Do you need lots of ATMs near you? DKB has a huge network, ING does too, but not equally good everywhere. Some people also still have standing orders or insurance tied to their old bank - you just have to keep an eye on that. But if it's mainly about the account fees for you, I'd say: go ahead and switch. It's really not that much effort, and these days the banks make it relatively easy for you digitally.