I disagree that people without a fenced yard should have small dogs as alot of your small dogs need to run as they are high energy. Alot of the larger breeds do very well as apartment/condo dogs as they are not high energy and get by with being walked a couple times a day.
Dazzle and I have been going to a local dog park that is on a very large piece of land and is fenced. Yes sometimes there are fights but usually they are squabbles and end with no injuries.The actual fights I have seen are owner caused such as an owner bringing treats and giving them to some dogs but not all that have gathered around them or bringing a valued toy and another dog grabs it.
My pets peeves about the place is it does allow big and small dogs. I think that is a mistake as a small dog could get hurt in play when the larger dogs all get going. Dazzle runs very fast being a sight hound and he plays tag so tags the dog he is chasing with his paw or his mouth so I get very nervous when he plays with the smaller dogs ( which he loves) as a little 5 lb maltese could get injured by a tag at his high speeds. Most of the little dogs seem to delight in playing with Dazzle.
Some people also bring very small children or even todlers into the dog park and they too could get knocked over and injured even by non aggressive dogs.There were a couple young kids that were grabbing collars to read the tags to learn dogs names and not all dogs like to have collars grabbed. I just think small kids do not belong at dog parks.They were also picking up all the smaller dogs and the parenst did nothing to stop them.
Another pet peeve is there is the group of women who are regulars that pull up the chairs and sit under the shade of a tree talking the whole time so are not paying attention to their dogs. I have noticed quite a bit of poop not getting picked up and I have never seen one of these women clean up after their dog. I had Dash with us the other day and his nose had been bleeding and tends to drip on his leg. Well he went over by these women and I noticed them all looking over at me like I had done something wrong . Then they sent over a child to tell me my dog had blood on his leg and maybe I should come check it out.

I told the kid he almost always has blood on his leg as it drips out his nose from his nasal cancer.
Ther are alot of dogs at the park that really do not "play " with the others but still enjoy walking around sniffing or sticking their heads in the gopher holes or interacting with people so I feel for most it is a positive experience. If the mix is wrong and a bit aggressive that day you do have the option to leave. If you learn to read body language and keep an eye on your dog you can do well at avoiding the aggressive dogs.
I do notice more aggressive behavior when puppy of say 5 months or so is there and often it is just an older dog teaching the puppy how to behave. At that age most dogs no longer cut puppies alot of slack and feel they should have manners. The puppies are not hurt but it can look frightening. I think it is important for the puppies to learn the correct behavior and that teaching does come from an older dog. There is a 6 month old basset hound that is forever being scolded by the older dogs and he just stands up wags his tail and goes on his way after a scolding.
Jazz and Dash spent alot of time at a park that allowed off leash dogs when they were younger and it was great. Dash still goes to a park that allows off leash play once a week to meet his play group and it is very important to him to go. Over the years Jazz has gotten too bossy and grumpy so she no longer goes. So yea I am a fan of dog parks. None of my dogs have ever gotten sick from the dog parks as most people that go to the trouble of going to the dog park are good owners and the dogs do have to have a license to come meaning they do have their rabies vaccine and since a vet must give that they are on a vaccine protocol of some kind. I think around here the dogs that don't get good vet care are the dogs that spend their lives in a back yard and have owners that do not take them out to places or on walks.
The indoor park sounds great for areas that get alot of rain or have cold winters or if it is air conditioned even areas that are too hot. We don't need it here as we are in Southern California right on the ocean so in the late afternoons we tend to have an ocean breeze that keeps it cooler then inland.
I do think it is great that the CEO of Unleashed posted his response as to why Pitbulls are not allowed and it is too bad that insurance companies feel the way they do about the breed.