However the topic is a change to any one anime.
So I'm going to focus on a show that was good, even excellent, but could have been unbelievably good with just one change. First, a quick checklist:
Excellent character designs: check.
Superb world building and design values throughout: Check
Surprisingly interesting characters: check.
Good plotting and story: check
Fabulous sound track: check
Animation budget: OOPS. Sorry guys, we kinda overspent on the other stuff.
Record of Lodoss Wars OAVs come on down! For those who haven't encountered this 20 year old series it is classic High Fantasy straight from the D&D table.
Sometimes you can even hear the dice rattling in the background. :)
Despite that the story works extremely well due to one of the most fascinating antagonists ever created backed up by fabulous design values.
Unfortunately it is often just as well that the music and artwork is so good because at times the animation is so bad that you have plenty of time to admire it.
So the one change I would make to the Record of Lodoss Wars OAVs: an honest-to-god animation budget to fully realise the vision that's there.
Day 1 - Very first anime: Robotech, Gall Force, Vampire Princess Miyu
Day 2 - Favourite TV series: Card Captor Sakura
Day 3 - Your anime crush: Oh grow UP already.
Day 4 - Favourite Film: My Neighbour Totoro
Day 5 - Anime character you feel you are most like (or wish you were): Kinoshita (Rocket Girls)
Day 6 - Most annoying anime character: Lynn Minmei
Day 7 - Character you’d most like to slap: Hiyama Hikaru
Day 8 - Most epic scene ever: Launch day - Wings of Honneamise
Day 9 - Saddest anime scene: The passing of the Fortune Twins - Nariya and Eriya
Day 10 - Favourite slice of life anime: ARIA
Day 11 - Favourite mecha series: Patlabor: The Mobile Police
Day 12 - Best instalment of a franchise you don’t like: Mobile Suit Gundam 0080: The War In The Pocket
Day 13 - Worst instalment of a franchise you do like: WXIII: Patlabor the Movie 3
Day 14 - Current (or most recent) anime wallpaper: I think I had a Silent Mobius wallpaper once.
Day 15 - A reality check for a genre you like: Romantic/Heroic Space Pirates
Day 16 - An anime classic that simply doesn’t work for you: Ghost in the Shell (film)
Day 17 - Best Background Music: Silent Mobius 2: The Motion Picture
Day 18 - Best Five-team: Silent Mobius
Day 19 - Change you’d like to make to any one anime: Add an animation budget to Lodoss Wars
Day 20 - Most ambiguous anime character
Day 21 – Favourite OAV Series
Day 22 - Animation studio you'd most like to slap.
Day 23 - Anime you think had the best, or most intriguing art
Day 24 - Favorite anime hero or heroine
Day 25 - Best anime villain
Day 26 - Your favorite harem anime
Day 27 - Favorite anime opening theme song
Day 28 - Favorite anime companion/summoned creature
Day 29 - Best Anime Music Video
Day 30 - Favorite anime ending theme