Consider adding a sibling inserter (+) button below the last current block

[RobStino]

Describe the bug
When typing away in a paragraph block the UI no longer presents the inline + button to the left. This button is available in other circumstances, but not when the most recent, or bottom, block is a paragraph block. This presents an inconsistent experience and mean the user has to click elsewhere (out of the natural top-down flow) to add a new block.

Recording of the experience -> https://d.pr/v/RX7SaO

To Reproduce
Steps to reproduce the behavior:

1. Create new post
2. Start typing (add paragraph block)
3. Note that the left/inline + button doesn't appear when hovering below the current paragraph block

Expected behavior
Expected the inline + button to appear when hovering below the current paragraph block.

Screenshots
https://d.pr/v/RX7SaO

Desktop (please complete the following information):

• OS: MacOS (10.14.1)
• Browser: Chrome (70.0.3538.77)

Additional context

• Gutenberg Version: 4.3.0

[RobStino]

@jwold mentioned that this behaviour was in response to the + button being distracting when writing. However, I think this current solution introduces a new usability problem.

[designsimply]

Noting some related issues:

• Confusing + button behavior #7271
• Add Block (+) is inconsistently used, possibly confusing #8363

[ocean90]

Some duplicates: #11445, #10519, #11329

[RobStino]

@designsimply @ocean90 Thanks for linking to the duplicates. I did look through the existing issues, but didn't spot them.
Happy to close this one if appropriate.

[mtias]

@RobStino if you want to add your thoughts to #10519 that'd be ace! Then we can consolidate the improvements to be made.