Marking this as fixed in the next release. A lot of public-facing phrases have been changed to sentence case.
Navigation collapsing has been implemented in XF2, but it only occurs if the Create drop-down will have both links. If it is just 1 link, then it is shown directly without using a drop-down.
Note that some phrases include the name of the wiki and not the word "Wiki". Names are still capitalized.
Regarding the sidebar entries you mentioned. These are not the default phrases in XenForo 2, since we only install widget definitions, and not any widget instances. Since you upgraded from XenForo 1, your existing Sidebar Blocks from XF1 were imported as XF2 widget instances. The custom names for the blocks from XF1 were used as the titles for the widgets. You can update the widget titles by editing the widgets in XF2's Widgets admin page.