Well...Sonic, that was a nice post. You asked all my questions...so I guess I'm gonna provide my shot at an answer.
In the Alpha, personally, I think the beam struggling was realized a little bit more effectively, if for no other reason than it looked great and by it's nature multiple powerstruggle participants were possible.
In the Alpha, I used to use a technique if I had high enough PL; I would fire a blast of HIGH power and aim it to the left of an incoming weaker beam. At the last second, as the heads cross each other, I would swing the mouse left, sending my beam into the other one. If I was strong enough--and usually I was--this resulted in my beam mashing the other one and pushing it in the direction my beam was heading.
So basically, I could use my super jacked blast to send the other dude's flying up diagonally away.
Then I'd detonate, and the beam's forward velocity pretty much insured that the blast would be somewhere near the enemy when I detonated the struggle. >:0) Added power for my blast, basically.
That being said; I think the initial beam velocity and strength should have a big effect on things. Like...in the example of the the four beams hitting the same area at the same time (or being pumped into an already-going struggle from 90 degree angles). Say the initial two parallel beams at east and west were generics. And the southernmost one was a half charged kame. But the northen blast is a fully-charged final flash. I think that they will have that be the determining factor as far as direction goes; it was like this in Alpha and I don't know why it got changed in the first place but either way.
Nothing was cooler then joining a struggle that my friend was losing, and sending the blast way off to the middle of nowhere to detonate harmlessly...or better yet, when I would use my jacked up final flashes to send the intense power struggle off in the general direction of other enemy players. :0)
I hope it's like that again. That was most of the fun I had with the alpha, with the absence of features, transformations, melee, and game modes.
And besides...how fun will it be if they have a system like that! Your intense power can manipulate other beams' directions!! THat makes for some great strategy (it takes time to blockstruggle a spirit bomb back...but to send it back with a bent final flash, and to add the extra power into the blast...hehehe! FUNN!!)
Man. I can't frigging wait. ESF rules!!