Kinda. The knee is pretty much Akira's best launcher since it does the most damage and juggles better although its hard to do consistently. Then again, I've seen people do fine with him without the knee, so I'm not completely sure. lol
Now I kind of want to see how I match up against you myself after seeing your match with Ten. Your styles complement eachother so I'd be interested in seeing how a semi-agressive Ein would do against that Ayane.