Its Sasuke's fault that Boruto has a karma seal. The losing an eye thing is harsh but he's lucky to be alive after all that.
It is a bit unfair that Sasuke has nothing that Hagoromo gave him, while Naruto still has Hagoromo Sage Mode and 8 Bijuu chakra inside him. Naruto has a replacement arm, but Sasuke is missing 1 arm. Now Sasuke is missing 1 eye also.
Naruto outside source power:
- 1 Tail beast
- 2 Tail beast
- 3 Tail beast
- 4 Tail beast
- 5 Tail beast
- 6 Tail beast
- 7 Tail beast
- 8 Tail beast
- Hagomoro Chakra that enables RSM.
Sasuke outside source power:
- Itachi eyes (only 1 now)
- Hagoromo chakra but nothing else.
Sasuke has got the short end of the stick.