Excuse my commenting without you seeing how I fight, but I think you can raise your Yoshi level much, much more...
1.) Have you noticed that you started doing better when you started using Sword Sweep more than once a round?
2.) Kamikaze should not be done without purpose! Good example is Deathcopter to Kamikaze. It's best used when you have advantage after a blow. And so you could see it, it hit Ryan just as he did ANY move.
3.) Where are juggle setups to Sword Sweep??? ... >_> They still work in Tekken 5!
4.) You don't use d/f+4, big mistake... SS+1 should be used as you expect high punches. beware this freaking backdash.
5.) Have you read my strats? FC,d/f+3, WS+4, f+1+2 is no juggle after this... do DGF 3! Not only it takes the same damage but also if opponent backrolls, you've got a free backthrow setup.
6.) Hardly any Flash I could see... you don't use u/f+4 and this is also a good kick.
7.) No D/B+2,2,2...??? This sets up great mind game!
8.) Ever thought about good juggles after Sword Sweep? D/f+1,2,D/B+2,2,2,2???
9.) After beign hit by two DGF moves, remember that usually people will want to kick you back, which is even more possible because they recover quickly. So the ever-working okizeme near wall would be DGF 3, DGF 3, u+3+4, D/B+3,3,3,3, FC,D/F+1, juggle...ooops? I already won?
You did third DGF. In that fight, I knew even before the kick that it won't work...
OK< I shall pause here... so what are the positives?
1.) Yesss! You maybe didn't realize, but already discovered the power of ssKIss technique.
SS KISS, that is: SS - Kamikaze. (called by my friends "The stunning kiss of Yoshi" :P). This wonder is highly evasive, and this is also the case in many of Yoshi's moves with the addition of ss to it. Well-timed evades even mid moves!!!
2.) I like the way you exploited any ducked high moves/throws. Good job! In the places where you use u/f+3 I use Sword Sweep
3.) Yup! u+3+4 after throw is a good-ass setup.
Generally, you did very well. As I watch this Kazuya, I would probably also lose with this guy.... but who knows, there's always a chance and a little bit of hope.