On topic, there are a lot of bugs with Nami on the PBE. Stuff like her Q halving her movement speed at random, her W randomly costing twice as much mana, her ult not doing anything, etc. I get the feeling it could be a while before she's ready :<
Lets see you make a game with this many champions and have it function.
You'd think after making 100 champions they'd get better at this