No, Lisp does not lack visual clues. But yes, very often people complain about Lisp readability. And that stems from the lack of familiarity, most people are familiar with the infix notation, but not prefix, used in Lisp. But I have seen many times, people who pick up Lisp (Clojure, Racket, etc.) as their first programming language - they do just fine, a matter of fact - they later find code written in other languages harder to read.

Unlike other languages, Lisp sometimes is difficult to read by just looking at it. Staring at Lisp code, examining its "static" properties without prior training indeed may pose a challenge. But there is a way to learn how to parse Lisp code mentally. And the best way of learning that is by editing it.

First, you need to find an IDE that supports structural editing of symbolic expressions (or s-exps). Basically, it would help if you learned a few operations:

slurp, barf, transpose, raise, kill s-exp, yank s-exp

Depending on the IDE you use, they may be called differently, and there may be more, these are the basic ones.

Once you learn those basic operations, you are now ready to untangle "unreadable" Lisp. The trick is to change the code while you read it.

Similar to how Tony Stark looks at the hologram of a model and moves his hands outward, forcing the hologram to expand, then he picks one of the parts, studies it, maybe completely removes it. He then would move his hands in a closing motion, and hologram would "assemble." That's how you work with Lisp.

So, for example, you read a function, if necessary, extract things, pick an expression, evaluate it, etc. Once you gain a good understanding of what the function does, you can undo all the changes, or if you think you have improved it - do save.

In other languages, when the structure of the code is settled, it's more challenging to pick it apart, move things in and out. You are forced to read the code "top to bottom." But in Lisp, code is a living, breathing thing. You basically feel like performing a surgery - you can tweak things, try them, and see instantaneous feedback in the REPL.

In other languages, code is "dead," until you save it, (re)compile it and execute it. And REPL in those languages is "crippled" and not a fully-fledged "true" REPL like in Lisp. Being able to pick any [sub]expression and evaluate it, without any kind of prior ceremony is truly liberating and empowering.

It takes time, for some it's hours, for others - weeks, but eventually you will stop seeing parentheses, and instead, you will see structure, consistency, and meaning. And Lisp becomes more readable than any other language you've used before.