The following are tweaked in the next release:
1) Unneeded block-filterBar removed.
2) Added block-row in a way that is as consistent with public:vw_feed_view as possible in this context.
But:
3) No change here, as the block-filterBar is sometimes actually used here for filters. It should be noted that nearly all content-list headings are wrapped in block-filterBar if the heading might be used to stack filters. If this is an issue in your custom style, then you may want to add a custom CSS rule to that style to address the clash.
4) If this were changed and you click "Post New Feed" from the wiki tab, then the tab would change in the other direction. Also, depending on the kind of feed you eventually create, the feed itself will open under either the Wiki tab or the Feeds tab. In general, the Feeds tab is used as a discovery list for feeds that actually exist under Wiki. It is only used as a wrapper for personal feeds which belong to a user and not the wiki.