As a brand new player to the game, please do not add repair costs. In just about every game that I have played that had repair costs in it, it was always a big turn off, and caused me to just abandon the game. It just feels limiting, and eventually becomes stressful, since you don't want to afford to die too much, or else the costs of repair may come to haunt you, thereby slowing down your progression of ships/tech trees down. Not only that, but I am pretty sure people do not like to constantly throw credits at their hard earned higher tier machines. What is the point of spending the time to unlock something bigger, badder, and cooler if you feel limited in how much you can play as it?
I agree. Its much better option to reduce credits gained per battle than introduce repairs. Players will not play at their full potential because they will be afraid of the repair costs. Both will achieve the same result credit wise, but the later introduces the negative factor which affects game(match) quality.