Yoshimitsu is a character who is jack of all trades but master of none. He has a punish, setup, or a panic tool for every situation possible, making him one of the best characters in the game at everything but playing solid neutral. Yoshimitu's strengths are skewed towards keepout tools and panic tools. He forces the opponent to play their neutral in a different way by dictating their offense because of the way that he uniquely defends. Spin, flash, and keep-out tools make it very hard to catch this character, and he avoids playing neutral normally to pull you into his own style of Tekken.
Yoshimitsu's general game plan revolves around keepout, this is his element. When he's playing keepout, there's no character that compares because he can set up his keepout offense by scaring the opponent with his panic tools. Mostly all of Yoshi's tools are meant to be reads because of how much damage they do, and the oki that follows up afterwards. He can choose to use a lot of launchers to get high damage or use a lot of gimmicks to highly confuse his opponents, and that sets him up to do either even MORE gimmicks or not making it obvious he wants to switch to a more keepout/passive style of play.
Yoshi's not an easy character to understand or play at a higher level, or if someone has general knowledge about Yoshi. This is because if he plays gimmicky and the opponent knows that he can get punished pretty hard for it, or if he doesn't want to play gimmicky, he can get beaten out by turtling players. He has no 50/50's without stances, and even then, his 50/50's are mediocre, so he has to work to try to open an opponent up. This is why his neutral is hard to master or understand, because he can't open up opponents, he sometimes relies on gimmicks to confuse them instead.
Strengths
His Manji Spins (b+3 or b+4) and Flash (1+4) make his panic tools better than every other character's
He has VERY long reaching keep-out tools that make it a consistent game plan
Yoshi's okizeme is endlessly confusing and also better than every other character's
Yoshimitsu's stances in T8 are much better than older games, having real 50/50's and plus frames
Weaknesses
Yoshimitsu needs to enter stances in order to 50/50 or have real mixups
Turtling is a difficult strategy for Yoshi to stop
His pokes are mediocre plus frames or mediocre situations on hit
He can easily be sidestepped to his right side
He can't easily get plus frames from either lows or mids
Heat System
Yoshi's f+1+2 is the longest reaching launcher in the game and has amazing tracking
His heat smash is massive damage with a wall and also has tons of range
b+2,2 is an extremely fast whiff punisher that is also a launcher
I17 and long reaching keepout tool.
It sets up for DGF stance (enter by holding up), and if they don't instantly jab, DGF is an extremely good option for what it has to offer
Flash.
Panic tool.
Doesn't have much range.
i6 or i8 in heat or NSS stance.
The fastest move in the entire game.
Requires skill, or a really bad opponent.
Makes people think twice about pressing while also getting tons of damage.
m, i6~9, -20 oB, +14c oH
db+3,3,4
This move has an infinite amount of variations to make it confusing for the opponent.
db+3,3 by itself is also good.
db+3,3,4,b goes into NSS to make it -6 and lets Yoshi move a lot better for whiffs.
Manji Spin.
Panic tool to get out of pressure.
Takes his own hp to spin.
Evades mostly every move in the game and sometimes homing moves because it moves backwards.
i20 low crushing move.
Homing move.
Low range.
Has a guaranteed hit after with f,n,d,df+1 (CD 1) if you're good enough.
It's safe, so it's good when someone delays a button or sidesteps
i20 and should only be used in heat or NSS.
In NSS, this move is -7 on block.
In heat, you can make this move +5 on block.
It's a launcher if used in heat.
Also extremely long range while having great tracking.
Running 3 is an amazing move that they added to T8, it has a good hitbox and gives Yoshi easy plus frames
M, i22~23, +5g oB, +13a (+3) oH
Stances
Dragonfly (DGF)
Enter manually with u+1+2 or by holding up after certain moves. Good for pressure after Heat smash, 3,1, f,f,f+3 and 3~4
Indian (IND)
Enter manually with d+3+4 or by pressing d+3+4 after certain moves. IND 3+4 is now a homing move and fast, so it's extremely good.
Also good for confusing the opponent, he can go into it off of db+3,3 or FC df+4
No Sword Stance (NSS)
Enter manually with b+1+2 or by holding back after certain moves. Very good stance to switch up your movelist, including your punishers
Kincho (KIN)
Enter manually with 1+2 or by holding 1+2 after certain moves. Good stance for pressure, but it's a little slow, so it's best used after f,f+3 or in okizeme situation
Flea (FLE)
Enter manually with d+1+2. KIN f+1+2 on block or uf+1,1 on hit are the best ways to go into this stance.
It's slow to go into the stance manually, but good at confusing the opponent if you do.
This is Yoshi's hellsweep, and if he doesn't do it after his NSS uf+1+3 frog jump, it doesn't have a real mid mix. You can fuzzy 90% of any mids that he would try to mix for this low (since most mids are faster than this low)
You can either interrupt this setup with a mid or block it and punish with a 13-frame or faster move
L, i17, -12 oB, -1 oH
db+3,3,4
The lows jail so you can mash a quick punish like WS4 to stop the mid kick at the end
f,f+3 into KIN
An i10 downjab beats every option he does except an unblockable, which is easily punishable by getting out of the way.
On block, you can SSR duck as an option select. This makes the high whiff and the mids from his KIN 1+2 will hit in a weird way, where you can punish him with a launcher once the move finishes