One thing that may assist specifically with the item purchase windows is remembering the pattern/sorting order that they fall into.
It tends to be sorted by Item Type -> Role (Tank, Healer, etc) -> Job.
You can then use the differing icons as a guide, for example all the belt items may share the same icon but it let's you know that you are in the right item type.
From there go by your recollection of the role and job order and arrangement, for example I know that the tank role is first and then under that role it is paladin, then warrior, then dark knight.
I actually use this technique myself to more quickly navigate the menus but it can also assist those that feel like they are getting lost in the word jumble.
Now for some brutal honesty.
While the devs could implement a trade back feature for tome and raid gear, which I wouldn't have a problem with, in the end it is a band-aid on one single aspect where your situation causes difficulty in your life.
I would highly suggest seeking out things that you can do on your end to assist yourself in overcoming your difficulties. Finding a way to improve your situation across your whole life is much more valuable than asking someone else to adjust to help with one small part.
You expressed that you see words more like images and therefore similar words can be very difficult because they look so much alike. That makes perfect sense and I understand where the difficulty comes from.
I feel a technique that I learned for speed reading may be helpful.
This technique was to not "read" the words letter by letter but to take in entire words and after much practice, entire groups of words at a time. Instead of using the letters to form the sounds that then determined the words, the words themselves would be taken in more like pictures or images and you use pattern and image recognition to be able to match the "look" of the word to the mental understanding or interpretation of a word. After a while you can then start stringing together "sentences" by recognizing patterns of the word "images".
While the technique was developed for speed reading, because it is based on seeing words as images, its concept of developing image and pattern recognition to interpret and "read" words may be very useful for your condition. It won't be easy and it will take lots of practice but if it helps the benefit will be well worth it.
In conclusion, I support the addition of a system to assist people with reading difficulties such as the proposed trade-back system (not as simple as people seem to think), however I urge you or anyone with such a situation to seek out real world assistance and to find things that they can do or practice to overcome, even if only a little, the difficulties in their lives.
Overcoming a disability takes a combination of understanding and acceptance from others and a good measure of personal gumption to fight back and not let the disability drag you down.