I'm looking for translated (JP or KR) novels that have things bad about them, but could be good templates for a fanfic specifically an SI-ish fic due to meta-knowledge and fix-its. Something like an isekai that you've read where you know you'd do a better job than the MC especially with his cheats. Or one where the hero protagonist is actually a hypocritical scumbag psychopath when looking at it objectively. Or just one where the MC is just a dense, good-for-nothing, cowardly, idiotic doormat. Please also include a paragraph of what was bad and how an insert could have done things better.
Well that hypocritical scumbag protagonist sure sounds like https://www.novelupdates.com/series/tsuki-ga-michibiku-isekai-douchuu/ or the hypocrite misogynist from https://www.novelupdates.com/series/hachinan-tte-sore-wa-nai-deshou/ . To be honest, I wouldn't write fanfic of either and sorry, but I don't want to look at them deeper again either... :/
I dont think this kind of fixing is good you would be taking the work of another and trying to twik it to be better by using hindsight and wish fulfillment to correct the authors mistakes/plot points and is honestly no better then the stupid ass chinese novels that outright rip off established series and even use said series artwork as their own. I personally downrate anything i see that is an outright ripoff either from the story itself if i read some and see its a ripoff or if the coverart is a blatant ripoff eg there was a chinese novel that has monsters working in a factory or some such that used the fucking HULK on its cover or the one that is basic wish fulfillment where they go through the established worlds taking overt he mc rolls of like onepeice dbz and so on such lazy hackeyed shit. there was a chinese manga i saw not to long ago that seems to be rather popular where the mc was the son of some mil officer and some super cyborg robot thing lady decides to live with him and act maidish and i was like thats fucking mahoromatic
I'd have to disagree with your first point. While I totally agree that there's a bunch of bad wish-fullfillment fanfic out there as well as those just simply profitting from the name of the original works, there are many good ones that uses the setting well and bring more to or give a different take on an existing work. The Trash of the Count's Family, Omniscient Reader's Viewpoint, The Novel's Extra, Kenkyo, Kenjitsu o Motto ni Ikite Orimasu, My Death Flags Show No Sign of Ending, The Villainous Daughter’s Butler ~I Raised Her to be Very Cute~, Common Sense of a Duke’s Daughter, etc. are all original translated works who nuffians know of that follow the premise and writing format of well done insert fanfics. They all also follow a fix-it objective. Everyday Life as a Supporting Character and In Another World with JUST MONIKA are fanfics that try to bring more to the characters and world of the source material especially in bringing depth and motivation to the heroines and try to bring more complexity and life to the world. What's Her Name in Hufflepuff, The Evil Overlord List, The One Ring, The Silver Eyed Prodigy, The Other Path, With This Ring, etc. explore elements outside of the existing canon characters and/or main conflicts. Even novels with even heavier and more blatant OP wishfullfillment focus like Chaotic Good and Broken Adventure can be entertaining and do more than just rip things off and zoom through the canon plot.