If a dog is OK with some dogs under some circumstances, is there any possibility that the dog could get to the point where she is OK with most dogs under most circumstances?

I got my dog when she was a year old. At that point she was living with other dogs and had issues (fights) with the other female dog in the house. I don't know the extent of the problem though.

She's now 5 and up until recently she was pretty reliable with other dogs. However, now, she will act aggressively with almost any dog who is her size (50 lbs). She is perfectly fine with any small dog. When I first adopted her, it's hard to remember since I never took much note of it, but every once in a while she would have an aggressive reaction to a dog while she was on a leash. But now, she's even gotten into a fight at the dog park so we don't take her there anymore. I would like to be able to take her places where there are other friendly dogs without her getting dominant with them. Is there any hope?
I've read in several sources that it is usually the owner's fault. However, I don't think that throughout the past 4 years I've done anything to reinforce this behavior except the classic pulling her leash tight when a dog approaches. She has always had interaction with other dogs, but, like I said, the problems are with dogs that are her size. I've also noticed that she especially has problems with other Huskies specifically.
I will NOT "alpha roll" my dog. That's one of the most dangerous things you can do to your dog. Most people end up getting badly bitten if they do it correctly. Why would I want to initiate forceful physical contact with a dog who is already trying to bite in the first place?