Here’s what feat chains do to the character building process.
You no longer can just read the feat list and think how X fits your character, you read the list and think well this feat would be cool for my character but I must meet the prereq feat…. *Looks at prereq, well that isn’t nearly as good or cool and I have to replace one of my other feats I wanted to take this so I can take the thing I really wanted. Is that worth it?
I’m not a fan of that process, especially the ideal implementation of taking something worse now for something better later.
I hear you… but the issues you describe are exactly the ones I have with the class system…
Each level of a class is a "unit of progress" which has the prereq of possessing the previous level of the class. Subclasses make this slightly more complex but ultimately it’s still mostly the same.
If we consider just the classes and ignore the subclasses, that’s 12 x 20 = 240 atomic units of progress, all but 12 of which (the 1st levels) are free of prepreqs (and even the 1st levels are not totally free of prereqs since you need 13 in one or two stats to have them in a multiclass build).
If I’m interested in one of those atomic units of progress, I need every single prereq (i.e., previous levels of that class), to get it.
Now if we reintroduce the subclasses we left aside so far, the complexity is even greater, because there are about 20% of these 240 units of progress that are not actually a single thing, but rather one of 4 different options, with their own extra prereqs (e.g., Illusionist 6 requires Illusionist 3, in addition to requiring Wizard 5).
Those 240 class levels + 200-ish subclass levels are spread across >100 pages. Furthermore, all that stuff includes a fair bit of redundant info (i.e., how much boilerplate is there with all the spellcasting class features that are almost identical except very slight tweaks, and all the Extra Attack, and Weapon Mastery, and Fighting Style, etc which are redundant across classes?)…
To call this simpler is an opinion, and as far as opinions go it’s legitimate. But it’s not necessarily a fact that it’s actually simpler. Maybe if you just pick one of the 48 subclasses randomly and build a single class character with it, then yeah, it’s simple. But compared to reading a list of feats and working out the prereqs, it’s hard to make the case that reading a list of class features and trying to fit them into a build is actually simpler.