Mordekaiser strong point?

Early game cause he makes his opponent's jungler strong

Probably mid because that's when he is both durable and deadly. Though in a one on one his late is still really good.

I'd say his ability to make a ghost and transform a game from 5v5 to 6v4 is valuable at any stage of the game, however.

Hard to say. Mord is seriously team comp reliant. Mid is when he's most generally useful, but if you have a comp that has respectable amounts of CC to make Mord's total lack of it irrelevant, he scales very well into late game in my experience.

Mordekaiser is strong at most points in the game.... being innately tanky from crushing your foes while dealing Phreak Puns levels of damage is something to be said... however being a short range mage can be difficult for our Metal Mage in Irons

hes broken. he has no counter play. needs to be balanced.

Mordekaiser is strongest in the early game when one opponent is forced to sit in a lane with him to prevent him from pushing. This is the time when few champions have boots or other movement-enhancing (or debuffing) items and abilities (or spammable long-range waveclear). Morde gets to beat on someone that can't afford to ignore him, but that same someone usually can't kill him because of the strength of his early-game shield and constant, easily-applied damage.

When mid game comes around, Mordekaiser tends to fall off because his enemies can simply walk away from him if he's looking to press an advantage/fight, and enemies with range can poke him at will. Morde himself at this point is either squishy enough to pop as soon as he gets in range to E someone (if he built mostly damage) or completely ignorable due to his lack of damage and CC (if he built tanky).

Some players will tell you that Morde is unkillable and does tons of damage; this is true if he managed to farm the hell out of his lane (he wasn't pressured by the enemy jungler or outmatched by his opponent), or his opponent fed him really hard. Even when Morde is doing well, he's easily kited and avoided, though his ability to push extremely hard for an AP champion makes him impossible to completely ignore (and difficult to confront without having enough damage to burn through his shield, spellvamp, and ult health drain; doing so is comparable to trying to fight Fiddlesticks without having any way to interrupt his Drain).

TL;DR: Morde is best during the early game when his binary, zero-CC, zero-mobility kit can be abused (constant low-cost poke combined with a shield that prevents out-trading his damage).

He'd benefit greatly from a large-scale rework (visuals included; the guy still has pizza feet), but Riot is loathe to give him such a rework because he's fairly iconic as he is.

Either early game where he can use his high damage, zone potential, and pushing to grind opponents out of lane or lategame, when his damage and surprising durability mean that he can act as a high damage bruiser while the tanks provide CC for him.