I don't see the point of the whole percentage thing.
Isn't that just going to make counting difficult?
I hope you're not serious.
People were predicting the end of the world if 1/2 points came back. The Skaven book brought them back and I haven't seen any real impact on the game. (Nor did it cause problems in all the previous editions...) I don't see how percentages will make the game more difficult.
As far as how it affects comp, we can't really say anything about that until we see how they structure percentages. If the rumor is even true in the first place.
While lapping around worked out to some sort of bonus at times, it could become such a pain in the ass to work out when you got into multiple combats, etc. I was glad it went away, though I wouldn't mind seeing some sort of bouns for having a wider formation than your opponent, similar to the rank bonus. ("Overlapping" in other rule systems... yes, there are other games around.)
I'm not sure I like the single round "speed combat." Sounds like WFB moving towards Warmaster. I left 40k because it became a meat grinder game and began to play too much like Epic. If this did end up happening, I would forsee an even greater emphasis on elites and heavy-hitters because the only point of combat would be to win it in an instant, and overwhelmingly. Gone would be tactics of tarpitting, or holding a line in order to move in flankers, or baiting & distracting powerful troops while you hit your opponent in their weaker spots...
But who knows... these are just rumors.