Just because a name is complicated or difficult to pronounce doesn't mean it's worthy of hate! Even though I don't even know how to pronounce this, I don't HATE it.
What. A. Beautiful. Name. I love it. I'd joyfully give it to a child, because it is so sweet. But so many people are so boring and mean and intolerant towards any person with a name which isn't short and 100% simple. I'd worry about how some would treat my child because of that.
As a Finn, I find Väinämöinen's pronunciation something like VA-i-na-MUU-i-nen. The ä and ö letters are not the same as a and o letters but extra vowel letters that the Finnish alphabet has, so they're not pronounced in the same way.