I don't think the below quote is true. Simpler systems are not liked because the simplicity has a trade off: the simpler the system, the less granular and more abstract the game becomes. A system with more rules is going to be able to account for more things in a more standard or detailed way. The draw back is having to learn more rules, but that learning curve comes with a pay off.
Simpler systems are not liked only because of easy-of-use and accessibility...
I think it depends. I can definitely understand that systems like A Time of War and Rolemaster have an unparalleled amount of details and there is no simple way to have such level of detail on a lighter, faster system. But i do think it's important to remember a few things.
Some times that complexity comes from just poor design. I don't have enough experience with ATOW to point anything like that but a good example for D&D 3.x/Pathfinder was the over abundance of extra attacks or other forms of action with different rolls as levels went up. The whole BAB progression was problematic in that at higher levels almost every character would have multiple attacks with different modifiers, resulting in much longer turns. Since those extra attacks were basically universal (although some classes had more attacks than others) they didn't even add as much uniqueness or "coll-factor" to characters and resulted in slowing the speed of the game without adding much simply because they were needed to retain the balance (As it's a system where balance is extremely important). In 5e there are still ways to get multiple attacks but they come from specific abilities and are far more limited, this both makes them more unique and significantly speeds up combat.
Now... To continue i think it's important to discuss 3 concepts on GMing and on RPG Design:
1 -
The Level of Crunch: You are probably familiar with the concepts of crunch and fluffy. Basically the more complex a system is, the crunchier it is. This is influenced by the other two concepts but is ultimately independent from them.
2 -
Player Types: The amazing "Robin's Laws of Good Game Mastering", while old and in several aspects dated, opened my eyes for this essential concept when GMing or designing RPGs. It's pretty simple, different players play the game for different reasons, they want different things out of the game. Robin identify several player archetypes, while cautioning that most players are a mixture of both. Those archetypes are Power-Gamer, which wants to be the best and maximize his characters; the Butt-Kicker, which wants escapism through doing cool and interesting things in game; the Tactician, which wants to be mentally challenged by the game and find ways to solve hard conflicts or problems; the Specialist, which wants to be really good at one specific thing and experience it; The Method Actor, which wants to immerse himself on the character and on the world; the Storyteller, which wants to create an interesting collaborative history; and the Casual Gamer which is either only there out of obligation or is there not for the game itself but for the social aspect of playing it.
3 -
The GNS Theory: This theory on game design divides game systems into archetypes which, like with the player types with real players, exist in a certain degree but in different proportions on every game. GNS stands for Gamist, which indicates systems which focus on the game,challenge and balance aspects RPG and are usually exemplified by Dungeons and Dragons; Narrativist, which indicates systems which focus on the construction of a collaborative narrative and storyline, exemplified by games like FATE and Dogs in The Vineyard; and Simulationist, which focus on simulating the proposed world (or worlds) and would include not only systems like Rolemaster, GURPS and A Time of War but also Savage Worlds, Tri-Stat dX, Vampire: The Masquerade and many others.
Now my point is: Not every player or system wants a high level of crunch. To the player of the Storyteller type having a crunchier system might both curtain his freedom to create the story he wants but also result on him spending less time doing what he wants, he would probably prefer a narrativist system with less crunch (Like FATE). The power-gamer and the tactician will probably want crunchier systems or at least a minimal level of crunch (like Savage Worlds, which is light in comparison to ATOW but slow in comparison to FATE) while staying on the Gamist and Simulationist sides of the GNS theory.
ATOW is a simulationist system with a high level of crunch which caters to the tactician player more than any other type and there is absolutly nothing wrong with that. Personally i would say that i would fit on the Method Actor and Tactician player types. The tactician in me wants this minimal amount of crunch but the Method Actor will adapt to any system, enjoying the abstraction of rules present on FATE and Burning Wheel but also liking how ATOW and Savage Worlds help through simulation to bring the world to life in a way that facilitates immersion while having systems that will create interesting surpises which will give me the opportunity to improvise and thing aobut my character on a different way.
Sorry for the long and convoluted post but my point is exactly that, different systems for different players with different motives on why they enjoy RPGs.