ForgottenLife
I personally don't really care about any sin seal or whatever but what I'm pretty sure about most people being mad about isn't you adding it in the story and nerfing his chakra reserves It was the fact that you totally blew off his magenkyo sharingan awakening and powers explanation(this IS important when you have an uchiha mc at the very least have to dedicate a whole chapter to it)in lieu of the sin seal awakening and its effects on the mc and his magenkyo sharingan(which we got no explanation on)basically you had two major things happen at once and then brushed one under the rug(the one we really cared about)while bringing the seal and its effects to the forefront(the we didn't care,know,or understand about. even now in this chapter your giving evolution to seal and having it mutate the mangekyo Sharingan without us having any Base knowledge on the original effects of his Mangekyou Sharingan. you should try to avoid mistakes like this in the future. hope you improve your writing in the future