I think this chest armor is too weak for level 40. As is it’s slightly below Chestguard of Perdition, but since Perdition is a set, it’s reasonable for Zolhan’s Battle Plate to be significally above.
It has average offensive stats for such level, but very bad defensive stats. 15% pierce resistance is quite low, I’d expect a level 40 item to have around 30-40% worth of resistances. 55 physique is only 137.5 hp and 27.5 DA. DA is okay, but hp is too low - even Perdition chest got 190-ish hp, not even comparing to DC’s turtle armor with 600+ hp. Avoid projectiles is nice to have, but doesn’t worth much.
Quite sad that an armor that was gifted to warrior of such caliber is so shitty.
My suggestion is to improve resistances to 24% pierce and 12% aether, just like empowered version. Empowered version would need it’s resistances boosted accordingly. Since it also lacks HP bonuses, I think adding +7% health bonus is reasonable. That’s the bare minimum. For extra appeal I suggest improving it’s +%physical and +%pierce damage, right now it’s just okay. I think it would be perfect if the item had better than average offensive capabilities with decent defensive capabilities, would make it stand out.
You don’t really have an answer that accurately reflects my position (“no”), so I just went with the last option, as I don’t think it needs a buff.
Other than the obvious “it’s a level 40 epic that you’ll outgrow extremely quickly, what’s the point?” I believe pierce resistance is more valuable than many of the other types, so ~15% of that is more valuable than a significantly higher amount of an elemental type, for instance. Also, you say that it’s “slightly below Chestguard of Perdition,” but don’t give any criteria you used for that evaluation. They are two completely different pieces with 0 affixes in common. Zolhan’s adds ~41% damage bonus, and Perdition adds merely ~19% (of different damage types, I might add). There are four epic level 40 armors, and Zolhan’s is the only one that adds physical and pierce damage as well as flat physique (which can be useful with % increases), so there’s also that. Finally, it’s right on par with all of the other chests, on average. It’s not quite as tanky as Perdition, but not as high of a damage boost as Fused Carapace, but nicely fits right in the middle.
While it might not be as good as Perdition for your character, it would be a significant upgrade over it for another character that is Nightblade heavy, for example. I guess the bottom line is that I believe its value over other similar items is very subjective.