I haven't gotten the ingredients yet to make a 65/65/65/65/65 PvP suit, and in any case, I'm very reluctant to try it on one of my good suits. There's no way to remove refinements, except to do the opposite on another piece. For my characters that use glasses or a Hat of the Magi, five refinable pieces means it's be impossible to remove everything.
Instead, I'm working on a combat simulator, based on the official formulas, to test a 65/65/65/65/65 suit in PvP. Against a mage, those resists don't matter, because of Curse. Against a dexxer, is 70% DCI worth it? Any serious PvP dexxer uses Hit Lower Defense, which means a cap of 45% versus 29%. Until I get the simulator going, my guess is that the 16% DCI is not worth it, considering properties that must be given up.
My PvM archers avoid taking any contact damage, so for them I'm in the process of making 70/75/75/75/75 platemail suits. The -20 hit to DCI doesn't matter for PvM.
For my dexxers that go against 100% physical damage monsters, I reforged an HP14 suit with DCI on each piece. A Crimson and Conjurer's Trinket bring me to the HP18 cap. I'm still acquiring refinements to get the suit to 70/65/65/65/65 and 65% DCI.
For my dexxers that go against monsters that deal elemental damage, I believe straight 70s and 45% DCI are balanced. One could refine a specific suits for, say, dragons and balrons, dropping the cold resist max to gain a little DCI. The extra DCI is worth it, considering their direct damage doesn't involve cold, and they do minimal damage with Harm. I personally won't be making many specific suits. I have enough specific weapons and little enough housing space.
I would love, LOVE IT, more than chocolate cake with mint frosting and a cherry on top, if refinement effects could stack. For example, five separate Scour of Defense for platemail could be used on the same piece for all the resists -- instead of the rare Invulnerability refinement that has just a 30% chance for the fifth resist! And the beauty of this is the ability to create suits like 75/65/65/65/65 or 65/75/75/75/75.