Implants are a fine welcome to the game, however, there are some things that are definitely Pay to Win and blatantly OP. Immunity to conc and flash grenades, absolutely not, conc 'nades are my primary attack and defense tools when I'm against heavy infantry e.g. a MAX. I conc him, and flank him before the effect wears off. Negating the effect with that implant completely throws any kind of legitimate tactical advantage and surprise attacks out of the water. Imagine this: you see an enemy MAX, it's a Hacksaw MAX, a big threat when engaged in a one-on-one, you assess the situation, throw a conc out, and engage the target from behind. Suddenly, the MAX swings around as if nothing happened, and one-shots you. This is not good for fair infantry fights, especially keeping in mind that players that won't spend a dime will get shafted big time, by players that pay for these implants. Keep this stuff off Planetside.
I have a small issue with 'awareness' if available in vehicles. Would nullify any stealth for aircraft.