Not a chance
Like not even a small chance
Paladins was announced to be 'in development' practically a year after Overwatch was already in a fully playable state at Blizzcon 2014
The character animations, designs and gameplay style are almost direct clones of Overwatch's and it's hard to ignore some of the more shameless rips they pulled off. Oh look, I've never seen a flying rocket chick, or a big tank guy with a hook, or Generic FPS Soldier #506034
With that said at least it is free... so if you can't pay the full price for Overwatch, that is understandable -- but know that you are dealing with HiRez. They are fickle developers who have IMHO burned their playerbase too many times in the past for me to trust them anymore. I'd rather cough up the price of Overwatch so I don't wake up in the morning to find Paladins has completely changed for the 20th time this phase