Wait. There is a bit of misinformation here. All the stats matter in arena, there is just a multiplier of 0.1x. Ninja stars also are calculated in the same way. Meeting someone with 300 less power means you have at least 3k power more in the "real" world. The arena also consider your team overall initiative: this means that if you have much more initiative on your position 1, but less on the others, your opponent will act first regardless.

We have discussed and tested this many times with the help of Achroma in one of the pinned thread in the strategy section of the forum.