Hi, I'm the Marth player that played Ryko. You may not have heard of me, but I'm very famous in America for my skill with Marth, and my overall knowledge of the game, and especially with Marth. I have extremely good knowledge in Smash Bros., and I'm good at Balancing. I gave a lot of input into Balanced Brawl, and I like your Jin Project. I would like to give some input.
Jin has extreme difficulties killing. I got tipper Dair to freeze and it auto-K.O.ed my opponent, sending them flying down and diagonally offstage fairly quickly while they were frozen. I would leave this in, because I tipper Daired many times while using Jin, and could not reproduce it ever.
I did not know about Remix Dash Attack, and in the videos, I was not realizing that the inputs on remix moves were so fast (I did not read this thread until just now, Ryko just knew I'd be interested). Remix moves are good, but since Jin lacks kill power, consider letting him remix utilt into DBup4. Also, consider having UpB remix into DBforward4 for an extremely flashy kill, but then make DB put you into the helpless state.
Ice car is good, but it's too fast, and too safe a poke. Make it come out frame 7.
I heard you changed dtilt. This makes me sad as a Marth main, but I'll have to see it before further comment.
Many of Jin's moves actually kill later than Marth, because freezing and not tipping makes it hard to kill heavy people. However, I probably did not use Usmash enough, since I was mostly experimenting. I would considering leaving Bair as it was in the version me and Ryko played, as I found it to be extremely good as a kill move, but hard to use. Fsmash can no longer kill, and neither does UpB or Counter really, especially if it's stale.
Please make a bthrow that deals no damage, but freeze the opponent for a very short time. Marth/Jin's throws are all good already, especially fthrow. Dthrow is better than Bthrow in every way for Marth, so give Bthrow a purpose for Jin. It should have moderate knockback, so it can't be followed up TOO easily.
In the matches, I also used Utilt too much, because it's one of Marth's best kill moves, and I was using it to juggle and freeze. Since Jin doesn't have Dancing Blade, I probably should've adjusted my strategy to more camping.
Side Taunt was very good, just increase the cool down a little.
I never knew about the super rapid jab, but it seems broken. Ryko's suggestion to give it 0 flinch so you can walk through it is good though.
Ice Car had a glitch where I would use it in the air, but go nowhere. I think this is due to having negative momentum. It's fine, because I can just remember to momentum cancel before recovering, but be aware of it.
Jab had an interrupt-able AT, where I could jab, and then cancel it almost immediately with a jump (and maybe other moves, I can't remember). This was hard to do, so I'd leave it in. Ice Car has an auto-cancel AT, where if you do it perfectly lined up with the level, you land on the ground with no lag. It's hard to do, but amazing, I'd leave it in as well.
Overall, I think Jin should remain with low kill power. Nerf the weak downsmash, and weak BackAir, so that you're FORCED to tip with these moves to kill. This way, tipper dsmash (which is extremely punishable) Usmash (also punishable) Utilt (still pretty punishable) and Tipper Bair (Safe, but hard to connect with) are his only kill moves that won't be stale. Nerf the weak hits of Dolphin Slash (UpB) to do less knockback. This move can kill light characters, but if it's stale at all, it won't kill anyone mid-weight until 140. This way, Jin is encouraged to use remix Utilt to kill with DBup4. Obviously it would be to press B immediately after Utilt. The moves look similar, so it's a very nice touch with a double up swing.
I picture that in the future, since Jin has so many pokes, he will revolve around camping, and racking up damage through poking and freezing, and then breaking your shield with shield breaker for a K.O.. For this reason, if you can somehow make using a fully charged shield breaker turn the background black, similar to MK's final smash, this would be a nice "Astro Finish" touch. If you can somehow write a conditional statement which will give Marth Final Smash power after you break a shield, that would be even better (it would probably read something like "If a shield breaks and an opponent is Marth, then Marth receives Final Smash power and if Marth gets hit then he has a 100% chance of losing his final smash power).
That's all for now. I'll play it again this Saturday, and tell you what I think of your latest version. I don't mind you nerfing Jin's kill power. I actually encourage it, but remember, keep tipper dsmash, tipper Bair, everything about Usmash, and everything about Utilt exactly the way it was. Nerf weak Bair and Dsmash.