When they had a ban on there being other Kryptonians they created a new Supergirl that was basically an artificial life form. It was just another keeping the copyright active thing, but the character was pretty well liked by Post-Crisis fans. I could never decide if she was a callus business decision, an attempt to throw fans like me a bone or another slap in the face to fans like me...it was probably a little of all of those, though. I'm glad they brought back a version of Kara Zor-El but the current version is not as appealing to the more naive, sweet and innocent original. Ironically Superman himself has a lot in common with the original Supergirl nowadays personality wise. But being decent and sweet and naive and fumbling is fine for a supporting character, but not for Superman.
I've always felt Krypto was good fun and I like him with Kon-El too. And I love Ace...it makes sense Batman would have a dog, police use dogs and so does the military.