Armor Upgrades and DPS: Should You Gold Out Armor?
In general, upgrading your armor to gold, while beneficial to your DPS, is not absolutely necessary to clear content. At most, you'll be seeing a 2k increase in damage going from Superior (blue) to Legendary (gold).
This is mainly because upgrading your armor only gives small returns. In general, the bonuses to your armor set bonuses are going to be small, and while it does boost your armor trait bonuses, if you're running the Shadow, the difference between all Superior and all Legendary Divines gear is only 2 percent additional crit damage.
Where it may matter would be for sets like Relequen and Siroria, where upgrading your armor makes the procs stronger. Since those sets "stack" their procs, increasing the amount from one proc results in a larger return.
But in general, upgrade your armor to Epic (purple), and then slowly upgrade to Legendary as time and money allows. You're better off spending that money to get proper sets or upgrading your weapons.