One consequence could be that it makes him an outcast. Controlling the dead is often seen as a dark and forbidden art, so his friends and allies might be afraid of him or turn against him.
There might be a negative impact on Naruto's own mental state. Dealing with the dead and using them for his purposes could take a toll on his psyche. He could start to lose his sense of right and wrong, or become more callous. Also, it could attract the attention of powerful enemies who either want to stop him from using this power or want to use it for their own evil ends. For example, Orochimaru might be very interested in this ability and try to either steal it from Naruto or manipulate him into using it in ways that benefit Orochimaru.
One consequence could be that it disturbs the balance of the ninja world. The dead are supposed to rest, and by controlling them, Naruto might be messing with the natural order. This could lead to other ninja clans or villages seeing him as a threat.
One consequence could be moral. They would have to deal with the ethics of controlling the dead. Are they disturbing the natural order? This could cause a rift between them and some of their friends and allies who might not agree with such a practice.
There could be a power struggle within the wizarding world. Some pure - blood families who have long held influence in the Wizengamot might oppose Harry's control. This could lead to internal conflicts, maybe even a split in the wizarding community between those who support Harry and those who don't.
One consequence could be that his friends start to fear and distrust him. After all, controlling people goes against the principles they uphold. They might see him as a threat and try to stop him, which could lead to a lot of conflict among them.
One consequence could be that his friends start to fear or distrust him. After all, mind control is a very invasive power. They might worry that he could use it against them at any time.
It could also change his relationship with other characters. Some might be in awe of his new power, while others might be jealous or fearful. For example, his rivals might see him as an even greater threat now and try to find ways to counter his iron - controlling abilities. This could lead to new story arcs centered around power struggles.
One possible consequence could be that Naruto is ostracized by some in the ninja world. Since controlling blood is a rather strange and perhaps 'creepy' ability to some, they might view him with suspicion or fear. This could lead to him having to prove himself more often in battles and interactions.
In some fanfictions, controlling the Kyuubi chakra might change Naruto's appearance. He could have some physical features related to the Kyuubi, like red - tinted eyes or a more ferocious look when using the chakra. Also, his relationships with others might be affected. Some might be in awe of his new power, while others could be afraid of him.
One consequence could be that it disrupts the natural balance. If Naruto isn't careful, his weather control might cause floods in some areas or droughts in others. For example, if he overuses his power to create rain, it could lead to excessive flooding.
There could also be environmental consequences. If Naruto isn't fully in control of his flood - controlling ability, he might accidentally cause damage to the local ecosystem. For example, he could disrupt the natural flow of rivers and flood areas that are important habitats for animals and plants.