Hello ArenaNet, this is a very bad idea. I will explain why. In this game there are 2 different types of damage, physical damage and condition damage. Power builds do physical damage, and condi builds do condition damage. Physical damage happens instantly as the enemy is struck, and most power builds have a rotation where they do a pretty big burst of damage. One such power build is the power soulbeast. It is great that you guys recognized how strong the burst of power soulbeast is and have brought it more in line. (Hopefully power soulbeast will receive adequate damage in return in the form of sustained dps.)
Condition damage, on the other hand, happens over time. Conditions such as burning, bleeding, poison, and torment are applied to the enemy when they are hit, and each stack of those conditions will deal a certain damage every second. That is why condition damage takes more time to "ramp up" compared to physical damage. However, not all conditions are created equal. Bleeding and poison do less damage each second, but they last for more seconds. Burning, on the other hand, do more damage every second and they are generally shorter in duration. That is why the "ramp up" time for burning is much shorter than the other conditions.
Condi firebrands are the only condi class that deal the majority of their damage in the form of burning, while the other condi builds such as mirage, scourge, renegade, and soulbeast deal their condition damage with conditions such as bleeding and torment. That is why naturally condi firebrands have a much shorter "ramp up" time than other condi builds. In fact, their "ramp up" time is more comparable to power classes than condition classes.
Therefore, with this proposed change, condi firebrands will outclass all the other condi classes in fractals. I assume your original intent with this change to encourage more condi builds in fractals, in reality they will be left in the dust by condi firebrands. Furthermore, for your average fractal group that is not able to hit the tight breakpoints before condi firebrands overtake power classes, this change will also catapult condi firebrands beyond all the other power builds in fractals (especially with the nerfs to power soulbeast and such). Now I wouldn't think that will make for a very great build diversity in fractals when there is already an abundance of condi firebrands as the other posters have mentioned (or if you just check the fractals of the mist section in the lfg). After this proposed change, even more people will stop playing other dps builds in fractals in favour of condi firebrands.