Well, the Freedom wasn't made for Kira but for some average coordinator so it would make sense.
So far there hasn't been a gundam that was crafted with his superior abilities in mind....but soon there will.
Also Freedom focuses on speed and heavy long range weaponry, good for taking down small armies before they can react...but that's not really his thing anymore. A good opponent won't let him use those wing cannons and he'll be left with just a saber and rifle...