PCMAN is a nice light FM that does just about all I need from such a tool.
The one major short-coming is the lack of configurabilty of the displayed info in detailed view.
It seems the columns are hard coded and only limited resizing is possible.
The big hole in what it offers is the lack of ownership and permission info. This is often essential when administering a system or understanding why some action is not possible to some files are not seen / directories are apparently empty.
Currently this is only available through considerable interaction with context menus. It needs to be directly visible (at least after configuration) in detailed view.
I see several short-coming which are all linked and could be fixed together.
1. Lack of owner col
2. lack of perms col
3. inability to reorder cols
4. description col is waste of real-estate, it's pretty obvious that a jpeg is a jpeg image file and a doc is a microsoft word file etc.etc.
5. min col widths are determined by the length of the column label ( lang dependent) . That is an unnecessary constraint once it has been read once. If space if tight (or a localised text label is long) this limits what can be seen. Eg I may want to squeeze 'size' down to enough to see xxxMB , many languages have longer labels. Description col is a waste. At least if I could reduce it to nearly nothing I would waste less space.
4 could be alleviated by 3 or 5 above.
IIRC Thunar allows simple selection of what file attributes are displayed and in what order. That is a considerable improvement in usefulness, for what I guess would be little coding.