Armanz is flat out ridiculous. It's not just his abilities, it's his stats as well. At level 60 he has 19k base HP, 108 speed and 1.1k DEF making him very fast, tanky and extremely hard to simply kill off even with Hegemon. Adding to his kit with full TM steal, his 3 turn A2 is realistically, 2 turns, meaning he can loop a same speed team permantely with only the 3% resist standing in the way. He would be less OP if his base HP was say something like 14k or so and his defense at 900ish to compensate for his kit. So squishy and needs to be in SS to survive Hegemon which at least gives him one hard counter.
It's very easy to build high speed and accuracy due to the ease of which perception gear can be obtained. It's not nearly as easy to build high resist as resist gear is DT locked or needs to be farmed. Compared to perception, most players probably have more good perception pieces than any other set in the game.
Do not understand why he was made so tanky with a broken control kit that has zero hard counters at present. Resist isn't really a counter as it's easier to stack accuracy than resist, and you only have to match the numbers were as resist needs to be a full 100 higher. Riho might be a "soft" counter as she can reflect the stun but she can't prevent the TM steal, nor can she do much to prevent the other 3 from destroying your team. Polymorph blessing at 6 stars is the only other "soft" counter that's entirely depedent on RNG.
Side note, some Hegemon math by the way (using our Hegemon as an example):
8050 attack, 330 CD, cruel+savage
Damage from A2: 8050 x 4.3 x 3.8 x 1.3 x 1.14 = ~195k raw damage
Assume 3500 defense (fairly normal stats mid to high gold V), 3500 x 0.7 = 2450 DEF/~68% mitigation
HP required to survive nuke, ~62k HP (without masteries or other passives), with masteries, ~57k HP.
As should be obvious, to survive a Hegemon nuke isn't difficult if a champion is built even remotely for defense. Hegemon's 3.8 base multiplier just doesn't cut it anymore when blessings have made everyone significantly tankier. Wager it's much easier to build a 19k/1.1k base to 57k/3.5k than it is to build a 1.5k/63 to 8k/330.