First of all, the multi-shadow ninja is one of them. Although everyone can use this ninja, Kakashi just can't. This Ninjutsu is forbidden because it requires too much chakra. Only Naruto, a ninja with a large quantity in chakra, can use it. If they don't master it well, they may hurt themselves. Chakra itself is not like Kakashi, and Saringan is such a big consumer of chakra, so ordinary shadows are probably the limit of Kakashi.
Sealing ghosts is also a forbidden art in Muye Village, which originated from the seal art of whirlpool clan, and its power can only be sealed even by bijuu. When Kyubi no Youko invaded Muye Village, Namikaze Minato quickly sealed Kyubi no Youko with the help of ghosts, thus avoiding excessive losses in Muye Village. Orochimaru, who is determined to explore the mysteries of the world, is comfortable with anyone. Even if he was sealed by Uchiha Itachi, he could be resurrected by Sasuke. Only in the face of three generations of Huo Ying, one hand can decide the whole plot. However, the price of such a powerful sealing technique is quite huge, and Kakashi certainly dare not copy it.
Speaking of Namikaze Minato, besides the ghost seal, there is another trick that Kakashi didn't give, and that is the flying Raytheon. Endurance, also developed by Huo Ying's second generation, is also banned in Muye Village, which is not something that ordinary people can learn. It is generous and glorious for Namikaze Minato to use Raytheon to the target in advance to achieve the effect of teleportation. However, he didn't pass on his specialty, Ninjutsu, to disciple Kakashi. Obviously, there is one consideration. Presumably, the chakra needed by Raytheon is also huge.
Chakra consumes, Bai Hao's art is absolutely the more chakra, the stronger the endurance. At present, only two people have mastered this technology, one is Gang Shou of Huo Ying in the Five Dynasties, and the other is her apprentice Muying. Cultivating this skill requires a strong ability to control chakras, which is not even learned by following Gang Shou's silence for years. You can imagine how difficult it is to learn Bai Hao's technology. Bai Hao's art is to close the daily chakra and release it at critical moments. Obviously, there are not enough Kakashi in chakra on weekdays, and even if they are copied, they cannot be used.
Kakashi and Sarutobi Hiruzen are very similar, both of them are all-attribute chakra, but they can't catch up with Huo Ying's three generations, and that is their own chakra. Sarutobi Hiruzen's five attributes of Ninjutsu are handy, and he takes turns to go into battle, enough to cope with most opponents. Where's Kakashi? You should carefully consider the use of Ninjutsu. In the later period, chakra was exhausted by the excessive use of Ninjutsu, and the ninja who brought the box lunch even carved a dog's head on the mud wall. In that case, Sarutobi Hiruzen's endurance and the style of play in Dalian will not be used by Kakashi.
Kakashi's chakra is really small, not enough to support him to complete a highlight battle. Payne's invasion of Muye Village is an example. He had to stay in bed for half a month after a battle. Only in the later period did he get promoted, not because he became stronger, but because no one lacked chakra in the later period.