The output of Start-SPMTMigration is in sentence form, and while you can capture it, you still have to parse it, which is exactly what you're NOT supposed to have to do in PowerShell.

Instead the Output of Start-SPMTMigration should be something like this
GUID Status Reason

c3cc7804-7164-4a2b-8996-7e51f319dea9 Passed
efd127ce-68f4-4d85-960d-5384ba561bef Failed The Target Site <URL> does not exist

I mean, you still have to parse the Reason, if you want, but at least you have fewer hoops to jump through just to remove tasks that are destined to fail from your migration.

The SharePoint Migration Tool should have a well documented, silent and scriptable installation process. The GUI portions of this product have interest to me, and yet, I'm stuck with 3 or four clicks to get it installed just so I can automate data migrations.

Maybe a Nuget Package? Chocolatey?

Migrated Web parts from SP13 to SPOnline don't include the chrome type attribute as it is and set to "Default".
So, if I have a web part that its Chrome type is set to "None", it's set online as "Default" instead.

Being able to host an on-premise Share Point Server (2019), that synchronizes real time bidirectionally with Office 365 Share Point. (To Improve Performance / Business continuity)

Also, it would need to have the options of cloning the sites and other pages from Share Point Office 365 to the on-premise Share Point Server (2019). With offering as much full functionality as possible.

Currently uploading files to onedrive is limited to 15GB.
With an increasing file size, especially with 4k content, the 15GB limit causes some inconveniences
Please
Increase limit of the uploaded file to 50GB or the highest possible level

Include timebased information like CreationDate,ModifiedDate and LastAccessedDate in the scan reports to gain insights on data in fileshares or SharePoint that might require archiving or disposition opposed to migration. By including this in the reports, these can be used for further processing.

Prompt for a user and password of the user who will run the service.

Would be nice to have the ability to move sites and content between SharePoint 2019 and SharePoint online with SPMT tool in both directions

Please write a post explaining the need to select the option for Migrating a OneNote as one file, versus a document library with many folders.

We set up Hybrid Search (CloudSSA) so that we can point users to our Modern Search Center (sharepoint online) while we run in hybrid for next few years. But document preview does not work for on-prem files. Per Microsoft engineer, this is being worked on.

Reason : Modern Search uses different preview or microblog service which does not have the ability. Classic search from Enterprise search center has the preview ability

Many of the 3rd party tools offer features to automatically replace illegal characters in file names and/or remapping illegal folder names such as 'Forms' at the root level for OD4B. It would be nice if SPMT also had such features.

In large IT organizations, especially organizations that already use Office 365 applications, often the O365 global admin is a different team or admin than the SharePoint Online team or admin. The SharePoint Online admin team who would have the SharePoint Online service administrator role, but not necessary the entire O365 tenant global admin role, should be able to run the SharePoint Online Hybrid picker as well as the O365 global admin.

Pretty much as per the title - add the functionality to create a migration job, and have it start at a particular time of day, pause when required, and then continue. The SPMT can use a lot of resource on the device it's installed on, and consumes bandwidth, so have it start after working hours, pause for the next day, and then continue, all automatically, would be very useful.

The current 2.1 release of the SharePoint Migration Tool balloons to occupy a huge amount of memory and disk space when scanning millions of files. I find this unnecessary for a program that is essentially creating a catalog of files.

After scanning 15 million files, memory usage is at 12 GB and the list.dat file is 45 GB.

Third party tools such as ShareGate and Metalogix allows the customer to migrate libraries with an option (setting) to leave behind the content. This is very common request from our customers needing to cleanup sites/content before migration but allows the migration of site structure. I have been asked if this is possible many time and I can only recomment using a 3rd party tool. This would be a great addition to our migration tool.