Could you show me the maths behind? If we look at the rings from the exotics perspective, we see 5 power, 5 precision and +3% magic find more on the ascended. An exotic ring with jewel has about 218 points on it, an exotic ring with +magic find has 126 points on it. That equals + 7 magic find to 92 points, which equals +1% to about 13 points. That is a 49 points advantage of the ascended ring (5 + 5 + 3 x 13).
If the other items have a similar relation (which they might not perhaps) and would have the some amount of stats (which they will not, cause there are differences), a person with 13 ascended items will be 637 points better than a person with exotic items. That is too much to be without consequences for fights. Maybe my calculation is wrong however.
It's simple, just like all exotic pieces have 13% higher stats than their rare equivalents, ascended pieces will have 8% more than exotics.
It's how items work in GW2, I don't see why Anet would take a completely different route when coding the ascended tier compared to all other tiers.
In my calc, I added 8% to what my current exotic set gives (including defense), and I ended up with those numbers.
Obviously, 80pow 60prec 110ar are pretty much non-factors in a fight.
What will make a noticiable difference will be the new Ascended weapons; weapon damage range is a much bigger factor than stats in the damage formula, aka (weapon damage) * Power * (skill-specific coefficient) / (target's Armor).
In order of importance, what determines the final damage the most is the skill coefficient (a little +0.1 gives a large damage bonus) which only devs can modify, followed by weapon damage and finally, to a much lesser extent, power (since it's the most beefy stat).
We see for a fact, in game, that there is little difference between a char with exotic weps and rare armor/jewels, and a full exotic character, while there is a noticiable gap between a full rare char and a full exotic char due to weapon damage range.
Until ascended weapons are released, there is no need to upgrade from exotics for WvW purposes.