Networking is an inherently complex problem. Attempting to simplify the problem by ignoring those complexities, rather than actually deal with them, misses the point entirely.
This library in particular demonstrates an unfortunate lack of understanding of why Apple has designed its networking stack the way it has. As a result, it needlessly duplicates interfaces and functionality of built-in classes.
Not exposing NSURLRequest means that there's no support for caching policies, or HTTP pipelining, or setting an HTTP body stream, or control over cellular access. Not using NSURLCredential or exposing authentication challenges means that you lose support for digest auth, NTLM, and kerberos, and leaves the user vulnerable to Man-in-the-Middle attacks for lack of certificate pinning and verification. Not exposing other delegate methods means no backgrounding support, no cache control, and no extensibility beyond what the original author envisioned.
AFNetworking is modular and composable. If you don't want to deal with its complexity, you can ignore a lot of it. If you don't need much, just use the built in NSURLConnection or NSURLSession classes (they're actually quite nice). But seriously, don't settle for a wrapper library that dumbs down a problem; you'll regret it soon enough.