I can understand that some fans of older editions are unhappy. They spend tons of time to master a super complex system until they finally manage to cheese the hell out of it and create godlike chars and suddenly the devs create a more simple system.
IMHO it´s not exactly that. Nobody wants to put himself through 200 pages of rules if you can do the same with 20 pages and there are lots of game systems that have some overcomplicated rules (Anima comes to mind).
The thing is not that the ruleset becomes more simple, the crux of the matter is that when you simplify rules you have to cut somewhere. Most of the time it´s superfluous content but sometimes it involves losing some key features.
Using D&D as an example: You reach 5e and suddenly the sorcerers are the only casters in the world that could modify their spells with metamagic (i.e casting a spell as a bonus action, empower, give it longer reach, or casting it silently), you have to choose between improve your stats or a feat, you cannot learn new skills, languages or tools after level one (besides a few subclasses), druids do not have animal companions anymore and and your option in combat for pure warriors (besides some subclasses) is Auto-attack most of the time in a "Yo, dawg, I heard you like attacking, so I will put an attacking option for when you are attacking with your attacks while using your attack to attack with your attacking abilities" way.
I understand people that are used to have more build and combat mechanics options in previous editions are a little disenchanted with some things of D&D5e (A fantastic edition in most aspects).
In the TT it´s not that a big deal because you could just ask your DM and RP what you want to do.
You may ask if you can taunt your enemies to attack you instead of your squishy party member, shout a battlecry to intimidate your enemies, try to destroy their shield with a heavy blow, shoot the cyclops´s eye to blind it, using a feint to distract them from your real attack with your off-hand weapon, disarm them or kick a table to take cover behind it, etc.
But in a videogame your "DM" only speaks binary, so that option is out of the table. So a more simplified ruleset translates into less fun things you can do in combat.
In that regard Paizo´s "Pathfinder" is a great game ruleset to translate into a videogame, because you already have a lot of combat maneouvers, arcane feats and lots of features you can use in and out of combat in the manual as core rules, so you have to put that in the videogame instead of relaying in your DM to allow players to do cool things in combat.
Using a videogame example, if you take a look at the Fallout franchise it evolved from a isometric rpg to a shooter rpg of sorts, but the games retain some of the features in fo3 and FNV. FO4 got rid of the skills&feats in character creation, using a simplified system where you just pick a perk that improves your character or you need to find a bobblehead in the world to use some ability instead of levelling up to choose it. And that´s ok because you do not need to know your exact "%hit" in a RT shooter or stuff like that.
But at the same time when they got rid of the "skills" they took away the uses of the skills when you interact with the world in Fo3 or FNV with characters or to solve some quests without using your guns. I liked using your medicine to cure wounded soldiers, explosive to disarm mines, speech or barter to use in conversations, or science to know about tech stuff...
In FO4 you seem to be trained to do almost everything (besides hack computers and unlock locks), use and repair any weapon you find including plasma weapons or flamethrowers, use power armor or heavy machineguns;.. No matter if your female character is a former lawyer because you just go and click on it and it´s done which is a thing I do not particularly care about in a RPG.
