The best way to deal with condis is to dodge the big condi-applying attacks, like Deathshroud2, Signet of Spite, Weakening Shroud, Shrapnel Nades, Prybar, etc. You shouldn’t expect to avoid/negate all condi damage (just like no one expects to avoid all power damage). Certain condi builds, like terrormancer with full life force, will have the upper hand vs D/D unless you specifically spec to beat them.
I’d strongly recommend taking Sig of Restoration over Ether Renewal for D/D. You get a lot more healing out of SoR because D/D is very skill-spammy. Also, you need to worry about covering your SoR against interrupts against competent players. If you insist on using SoR, you can move the 20 pts from fire to earth. Taking stone splinters will even out the loss in damage from power (pretty much all your D/D skills require that you be w/in stone splinters range anyway). And then take the earth master trait that grants 2s AOE stability whenever you swap to earth, which you can use to cover ether renewal.
Otherwise, your stat spread is probably fine depending on playstyle. Celestial is less useful in WvW than in sPvP because everyone runs -40% condi duration food, so unless you focus on +condi duration, your burn uptime will be significantly lower.
As far as traits go, Spell Slinger is unecessary w/ D/D because you can maintain 20+ stacks of might by blasting your fire fields (also, take sigil of battle). I’d again consider shifting those points in fire to other traits. For example, taking cleansing water (gives more reliable condi cleanse than cleansing fire), and stone splinters (for the +dmg modifier, to make up for the loss of power from taking points out of fire). If you need more survivability, taking elemental shielding will give you near perma-protection if you consistently land your magnetic leap through ring of fire. But it sounds like you are mostly struggling with conditions, in which case I’d go w/ stone splinters to down the other guy faster.
Fighting against a condi class is all about killing the condi class before he whittles you down, and dodging the big condi-bombs so you have more time to whittle him down. You shouldn’t expect to be able to ignore a condi class forever, although in some cases it is certainly possible to build that way (at the cost of being way less effective vs. non-condi classes).
