We have a webservice on which we have a PowerApp connector that enables PowerApps to run any macro, vba procedure/function, opening of a form to fill in text-fields and/or perform the equivalent to buttonclick-events in an Access Application. If MS-Access out of the box could configure and enable a webservice on the machine it's running and thus would enable a PowerApp to be a cloudfirst/mobilefirst frontend presentation layer, MS-Access 2019 would really become something new. When the Access application has linked SQL-tables to SQL-2016 or up, it can easily delegate the creation of JSON to SQL-server, but I wouldn't be surprised VBA already has JSON functionality in Access 2019.

In Access I often use the criteria Intellisense/Builder to help me get the vba string to drill down to a deeply nested subform. But Intellisense/Builder gives up about 3 forms in. It would be nice to be able to drill down further with the help of this tool.
I am by no means an expert at Access but over time have created several useful tools over the years, with the help of many Access experts on line. I created a very comprehensive vacation calendar used by over 200 people (tied to an sql back end) for my employer prior to my retirement. So, any tools that help ease the burden are always appreciated.

Give us the ability to request a partial Compress & Repair at the table level within an opened database.
It should not be impossible to compress database records and disk pages at the table level, bypassing and freeing up any space no longer needed for deleted data records and index entries.
Given Microsoft refusal to consider revamping the database Access database files to allow for larger databases, then giving us the ability to better manage the available 2GB of space by making incremental requests to compress & repair thins partially at the table-level could be a meaningful compromise. This could allow us to enable "paging-style" approaches with which to attack larger data files and import/export tasks which are presently beyond the reach of MS-Access databases.

Access needs a quick way to get a good solid installation of Back-end and Front-end databases including a registry edit for Trusted locations and versioning.
It should also include the ability to:
Add Icons,
Add Desktop and other shortcuts,
Allow user to accept an ELUA (End User License Agreement)
Run simple scripts,
Install with full windows trust. (maybe with a certificate?)
An uninstaller.
A check for updates function.
Install support files into specified folders.
Read simple system values and react accordingly (eg if 64bit systems then install 64 bit ODBC Driver)

Also it would be nice if it could notify the user of a new application Version (via a Web ini file or similar?)
Optionally install the Access Runtime.

This would lead to massive time saving for developers and make installations quick and identical across many users...

Old versions of office allowed users to install on any hard drive they wanted. The current office 2016 consumes up valuable hard drive space for the Operating System. Allow the user to decide where they want it installed. To make it easy have a express or custom option for installation. I have seen many companies use this option it allows easy installation for those who are less tech savvy and those who have experience to customize their installation. I use Visual Studio 2017 and it allows an installation option. THIS IS A MUST most people have small hard drives for the OS especially SSD which are about 140 GB which is OK for an OS itself.