Deadman's Plate Is Still Weak - A Suggestion & More Defined Identity

80% gold efficiency with a mostly utility passive doesn't seem that appealing. It's true that at 79 stacks it's gold-efficient but that disappears the second you use it and even at max stacks it's just 105% gold efficient. Deadman's fully stacked only does 100 single target magic damage once and it's used up even if you attack a monster or minion. I don't mind this at all because it can make clearing more efficient while also providing situational windows of power but the point is that it's not 100% uptime like for the passives on Thornmail, Sunfire, Randuin's etc.

Randuin's has an AoE slow and the 20% crit. reduction is always useful as long as they have a champion buying crit. such as Yasuo, Cait etc. It also reduces AS by 15% which can be very helpful for your team. Sunfire's not really in the same class but 43 magic damage per second is nothing to sneeze at and can apply in AoE (helps pushing too). Thornmail has grievous wounds, does 35+ return damage to any attacker, cripples their AS and provides 40 more armor at the expense of 150 HP. All of these items seem a lot better either for your team as a whole or your own power.

Deadman's offers more subtle power in terms of play-making and utility but it's just not on par. When I think of utility, IBG comes to mind. It offers a large slow zone, Sheen damage for a fast power spike and a massive 20% CDR. The mana on IBG is excessive and I'd gladly trade it for some HP but it still fits utility builds better. If Deadman's is to compete with this while being 200g more expensive, it should offer some CDR too. 10% CDR is worth 266g and that's a reasonable spot for it.

IBG would still be the utility Sheen item with the most CDR on an armor item but Deadman's would be better cemented in its category as the play-making utility option and it would start to appeal to more junglers too. It would fulfill a very important niche as a CDR + HP & Armor item. Abyssal has CDR, Spirit Visage has CDR, Adaptive Helm has CDR. There's a gap in itemization. Currently, IBG is the only aggressive armor item to offer this combination and it's not good on manaless users or if you want some protection vs magic damage too. Plus, IBG is about being sticky once you reach a target while Deadman's is more about getting to that target in the first place.

EDIT: If 10% CDR sounds like too much of a buff, perhaps the slow can be increased by .5 seconds. This is a decent place to start because it focuses on its play-making aspect - solidifying its identity. Just test various options but don't weaken its identity. Although, I'd rather have 10% CDR and fewer defensive stats because I don't buy Deadman's for the greatest ban/buck defensive slot item. That usually ends up being Randuin's.