Trinity Force will once again be a good item for Mordekaiser

He doesn't need the crit. So this is not a deal.

However the extra cooldown reduction really benefits Mordekaiser, especially because it is so difficult to get CDR when you are manaless. With Ionian Boots and Zhonya/Abyssal you might even reach 40% CDR easily. With runes, you can even forgo one of those items, or even both.

Also, the attack speed buff is actually very useful since it lets Mordekaiser hit his Q faster. The extra attack speed serves no other purpose, though, since Mordekaiser is mainly a caster.

oh, and Triforce became cheaper. Although not that much, this lets Mordekaiser complete his build faster.