Just a guess on my part, but the ebooks that are published by well established pbook publishers often seem more problematic than others. I cannot help but think they are still stuck in the pbook era where you had to choose a good font(s) and carefully layout each page to make it aesthetically apealing--meaning the publisher strictly controlled fonts, font sizes, line justification, line height, margins, etc. However, for ebooks it is almost totally different as most of those format settings in most cases should be very generic in order to let a reader (device) and/or a reader (person) render the ebook to their liking. I think it must be difficult for the big publishers to deal with two completely opposite publishing models.

Another problem I see with publishers big and small is a lack of understanding when it comes to HTML and CSS. Part of this is due to their using conversion software to convert pbooks into ebooks. Even converting an ebook into another format using a program like calibre turns out terrible HTML and CSS. A well formatted ebook should use perhaps up to three levels of headings and they should use h1, h2, and h3 tags. Paragraphs should be contained inside p tags and CSS classes used to differentiate between different paragraph styles. There should be NO font-family CSS statements in order for user customization to go unimpeded. Et cetera, et cetera. Yet I often see ebooks where they use anything but the standard tags. Headings are often placed in p tags. That horrible span tag is way overused when it can often be replaced with good CSS. And they should use em rather than pt and px when designating sizes due to the widely differing screen sizes for available devices. In short, the problematic ebooks quite often have terrible HTML and CSS. Both HTML and CSS are fairly easy to master, so they need to get a book and study it. It is not uncommon to see a mutil-page CSS file for a 300 page book! Ebooks should be simple in formatting and if the publisher cannot create a very nice ebook with a dozen or less CSS styles, then they are over-formatting. The K.I.S.S. philosophy (Keep It Simple Stupid) definitely applies to ebook formatting.