You are interpreting Google guidelines completely wrong. Try to use text instead of images to display important names, content, or links - try to use text instead of images are the key words here. By that it means, your important content on the site must be placed as plain text, not as image. This is a basic rule for beginners who like to keep font styling and some kind of visuals, but forget about plain text content indexed by SE.
If you locate mentioned Guidelines for "links", you won't find "keyword" links mentioned somewhere. "Make a site with a clear hierarchy and text links", "Offer a site map to your users with links that point to the important parts of your site", "Check for broken links and correct HTML", "Keep the links on a given page to a reasonable number (fewer than 100)" etc., but nothing about what you say and what is discussed in that topic.
If you think a bit, you will find this schema logical. Keywords in links are meaning NOTHING for SE, just because if they would, then everybody building a site, could make internal links keyword riched, and every site would have the same ranking as other. What's the sense?
I recommend you - relax your brain and forget about this thing. If you locate miniBB.com forums in Google, you will see all pages are indexed great, despite our URLs are not keyword riched.
There are much bigger number of problems appearing, if you decide to convert URLs from page titles, you can't even imagine, how stupid, ungrammatical can be users creating new topic subjects, and what is appearing on the output finally. We have very strong politics about that and we have no plans to change it.