I selected 4. Both are necessary to have, and likely about equally irritating when balanced poorly. Instead of demonizing both, lets admit that both need to exist for us as the player-base to have options.
Both are going to be irritating when they are in an unbalanced state. Our bias determines which one we hate worse, and the negativity is kind of annoying, honestly. "High skill"/"Overloaded" players seem to picture their opponents as little more than vaguely sentient rocks with thumbs, somehow beating them through superior numbers without ever lifting a brain cell . "Stat-Stick" players see their opponents running around with encyclopedia-sized kits, dashing around at the speed of sound and seem to be under the impression that any loss on their part is because the champion can do too much, rather than simply considering ways in which they can play better. Yes they move quick, but their numbers are a butter knife compared to your battle-axe.
I find the "Overloaded" champions mildly more irritating to fight when overtuned (and more difficult to balance, conceptually), but only because I play stat-sticks almost exclusively. But swiss-army-knife champions are essential and do need to exist. They are incredibly fun to play, even if the investment required to learn them properly is far longer (average win-rate on Yasuo, for example can sometimes hover as low as 45%, even with some of his mains winning far more frequently). The trick is making the floor low enough(a newbie should lose more at first), and the ceiling attainable without being idiotically high (even the most veteran akali players shouldn't lick 80% win rates unless they are actually faker).
The issue: Ego players: Losing is not always due to the opponents champion being overpowered. Sometimes ya just get outplayed and learn better next time. Overload champs are GREAT with this as they generally have a lot more of a variety of options to make use of in a given fight. The trap a lot of difficult champion mains fall into is thinking that because their champion is harder, they deserve even the wins they really didn't earn yet (give it time, the kit has the answers).
On the other hand, you need simplicity. League of seasons 1-5 was a land of stat-sticks, and was still quite fun, there were far fewer "overloaded" champs to contend with. Not everyone is a high-mechanical player. Simpler, less complex champions with stark strengths and weaknesses are fair. As a player, I much prefer spending time considering where to be/what to do macro-wise, than using the incredibly limited gaming time I possess trying to drill specific lee sin combos. But the numbers have to be fair. Nobody fights Garen/Darius/Morde at the moment and doesn't feel a little irritated at how little effort is needed to dominate with these folks at the moment. Champions of this type should usually have clearer weaknesses, and more stable, but slightly lower potential win-rates. (~55% win rate averages should NEVER be a thing, particularly with higher pick rates.)
The issue: Autopilot players: Without simple champions, what are the folks playing their off-role going to do, commit suicide? But you probably shouldn't be able to shut your brain off, afk top, and still score a serviceable win-rate in your off-position without having to actually play the map.
People might be more upset about "Overloaded" champions recently simply because so many of the newer offerings to the champion roster fall into that category. Earlier seasons of this game had FAR fewer high-mechanical difficulty swiss army knives, and other changes make the game feel less fun to them, so they look for something to blame. Stat stick players hate the Akalis of the world, and vice versa.
In the end, I think both sides could be happy. Simply make fights more satisfying again. They are too short, and one mistake is far too punishing for players to feel that their gameplay decisions matter.
TL:DR: Don't point the finger at champion types, Blame Rito for crappy balancing.