Maybe I'll give the Zahn novels another try. I mainly just remember finding the prose pretty stiff.
Nobody was going to nominate Timothy Zahn for the Nobel Prize in literature, you're right. But by and large his books (not just the Thrawn trilogy) made for entertaining stories that kept you turning pages and enjoying the experience. Even the Thrawn books had some lame plot elements (I personally believe that anytime you introduce clones into a novel or comic book you should go to Writer Jail for a mandatory 3 year sentence). But they were always fun to turn off your brain for a while and read. The same thing goes for most of the "Rogue Squadron" books.
Sadly, the rest of the Expanded Universe varied wildly from interesting and fun (Luke and his son's Force User Road Trip in "Fate of the Jedi") to dull (many of the earlier EU books) to depressing (most of the Yuuzhan Vong invasion which was just a way to induce PTSD in the next generation of Jedi) to full-on WTF (the Jedi council holding press conferences in "Fate of the Jedi" or the string of '90s book after book about zOMG somebody cloned the Emperor [again] or is rebuilding the Death Star [again].) There were some real gems in the EU but you have to pick through a lot of crap to get to them, and even then you won't get the full impact of some of the plot/character arc elements if you didn't wade through all the dreck that came before. So your time is probably best served avoiding all but a few of the most highly-reviewed ones.