1. What is your idea?
Enrich the dataview's format settings. In particular the block-specific #format settings of a layout.
Currently, the several formatting options I know are :
- use row templates for the ByRow entities
- use block formatting options (Dataview Menu > Layout > Block configuration > Format): I can set foreground and background color of the cells, but no border setting (border style, colour, thickness ...)

- use dataview settings to format further (Dataview Menu > Settings > Format > ...): I can set foreground and background color of the listed elements, but no border setting (border style, colour, thickness ...)

What I wish to add is (feel free to add more in the comments):
- ability to set border properties for Label, Value, Total, Grand total of a specific block of a dataview. Example with
- double border (top and bottom) for the grand total of each block
- thick bottom border for the label of each block:

- ability to set properties at dataview level (apply to all blocks) for headers, GroupBy, Grand Total beyond the foreground and background colors, e.g.
- text in bold, e.g. the grand total line of the table above: it has a bold text for TOTAL and the four total values.
- borders settings (border style, thickness ...)
- (ADDED 11th oct 2018) ability to set properties (i.e. bold/italicised, left/right/centred, font/size chosen) to
- Layout title
- Axis names (used as titles)
- Axis cells, e.g. in example below, it is not possible to centre the content of Quarter and Month columns

2. What specific problem are you trying to find a solution to, or what new scenario would this idea respond to?
This idea is maybe quite a small detail, but this enrichment would helps building a BOARD application using reporting standards as suggested by the ibcs ® standards (International Business Communication Standards).
These standards aim at providing a consistent reporting set for the user, so that he can very quickly know whether he is looking on actuals, budget or previous period figures (for example).
I give an example for a report table (Source) using IBCS standards so you can get a feeling on where I wish to achieve:
Actual, plan and forecast figures are distinguished
- in the headers text and
- in the headers' borders of the table: bottom double border for plan, thick border for actuals, hatched for forecast

3. What workaround have you found and used so far (if any)?
a few workaround with labels or linked dataview might be used, but they work only for small and static dataviews, their print or export is not really acceptable by a customer, the drill-down function on the dataview would open a new dataview without the borders created by the workaround and so on.... See the question I asked regarding this topic.