And I would have suggested to wait with the update until they are actually finished before replacing the old wiki - with some outdated content, but working well - with something much worse. The most positive reactions to the new wiki are like "wait until they are finished", I wish they'd take a hint from that.
The sidebar made perfect sense, especially because there was only a selection of links. Some pages are just consulted more often than others... I suspect the item/weapons/armor charts should be a prime example. Looking at your level, you can probably recite their content like poetry. Others are not quite there yet, and it helps to just find the one table you're looking for with just 1-3 clicks. If I have to type, search and find the right result, or memorize how to navigate through several pages, some badly structured, to find what I'm looking for, the wiki isn't particularly useful for me. And judging by other forum comments, a lot of people feel that way.
This whole new wiki business somehow reminds me of Microsoft and "here-it's-new-take-it-or-leave-it-lol-okei-we'll-leave-it" Windows 8...