I really think it depends on the dog park you choose. Once she was a couple of years old and full grown, I took my last sheltie fairly often.
We lived in a big city, Calgary, with leash laws and it had the only really large fenced in area where she could actually run free. The set up was also pretty nice with entrances at each end of what was essentially 2 very large fields seperated by a border of trees. People who wanted to socialize generally stuck to the middle or near the entrances and those who wanted to run their dogs would head forthe far corners. There were no rules about this it just seemed to happen and folk mostly respected if your dog preferred to not be bothered. In all that time I never saw any aggression or bullying like in these videos or we would have been gone never to return. The worst thing was usually someone looking the other way while their dog took a dump and not picking up. ( almost always someone who had a large dog). The park wasn't all that popular, far south end of the city near a HWY, and I was lucky to be able to go on a weekday morning when it wasn't terribly busy. She never played very much with the other dogs but I saw a huge improvement in her confidence after only half a dozen visits, and she loved the opportunity to really run.
My daughter lives in Calgary and they have a corgi - quite often they go to "corgi meet-ups" at different parks and they've really enjoyed that as a way to meet other Corgi people.
I don't think puppies and tiny dogs belong in dog parks - they look too much like prey, and even a friendly playful dog could hurt them merely by jumping on them.
It's highly unlikely that Hanna will ever get to a dog park. We have access to miles of mostly deserted beach, 25 KM of hiking trails out my back door, and I have a friend with a 100 acre farm, so she will get plenty of opportunities to run. We had puppy socialization and will continue with obedience next session, we see dogs on out walk and sometimes we vist with a friend who has a toy poodle, that's enough exposure to other dogs.