For your research, take a look at this site:
There are various videos posted and some deal with knives. I'm pretty sure it'll give you some new insights on your practice.
As to your practice -- I can offer my opinion/advice, but I'm not an expert.
My first thought about the use of the knife in your video was that it was being used in an amateur fashion. In other words, basically, slicing back and forth and some stabbing. you can do a whole lot more with a knife.
If you have a knife, it's a deadly encounter. Period. Treat it as such. In other words, if you've got the knife, then use it to kill. Don't mess around with it. Slash, cut, pick, stab, core, or flay arteries and organs. A slight flick of the wrist can move a knife from outside an arm to inside an arm, where nice, juicy arteries are located.
If you aren't interested in using the knife to its full advantage, then my suggestion would be to not use it at all. But, that goes back to the previous paragraph -- a knife is a deadly weapon. Learn to wield it effectively.
Personally, I think trying to apply aikido to knife is backwards. Learn how to use the knife (and aikido doesn't teach that), apply aiki (body structure) to your knife work, and then find a way to blend all that to aikido.
But, that's all just IMO.
there are ups and downs to reversing the blade (not taking into account blade in or blade out on the reverse). One major down to that is that you lose your reach. With the blade held outward, you have extended your reach. You can pick with the tip and stay outside your opponent's striking range. Even just barely making your opponent's range, you can slash a wrist. With reversed blade, you have to come well into striking range. Also, in a clench, you can't drive the point up under the opponent's ribs. Other stuff, etc.
Positives are it's harder to knock the blade from your hands. Just blocking (with reverse, edge out) with the knife will probably cut your opponent. Trapping is very effective. All it takes is to trap a wrist and then twist the knife around a bit to cut the opponent's wrist as he/she pulls away. Or better yet, trap a bit higher and flay the inside arm as he/she pulls the arm away. Other, nasty stuff, etc.