TL;DR: Make Phased Deployments for Applications the same as Phased Deployments for Task Sequences where you can create up to 10 phases and manually initiate the second phase of deployment.

Explanation:
Currently in 1806 although you can create a phased deployment for an Application, you're limited in two key areas:

1) You cannot manually create phases for an application
2) You cannot manually begin the second phase of deployment for an application
3) You are limited to 2 phases for an application

In our environment we follow a controlled graceful deployment process where an Application Model application is deployed office-by-office to prevent flood of support calls should an unexpected situation arise. Since we have multiple offices across the globe, a single application may have as many as 13 deployments, although it's typically around 6.

Phased Deployments is the solution here but it's usefulness in the context of Applications is limited. If it could match features available in Task Sequence deployments it would be of significant value.

Documentation:
https://docs.microsoft.com/en-us/sccm/apps/deploy-use/deploy-applications
https://docs.microsoft.com/en-us/sccm/osd/deploy-use/create-phased-deployment-for-task-sequence?toc=/sccm/apps/toc.json&bc=/sccm/apps/breadcrumb/toc.json
https://docs.microsoft.com/en-us/sccm/osd/deploy-use/create-phased-deployment-for-task-sequence

Currently when we want to run PowerShell commands in an ConfigMgr Application we need to wrap them in a script or run them with powershell.exe -command and make it a oneliner. This is because it's always triggered from cmd.exe.
Would be nice to be able to choose to directly start PowerShell.exe and just run the PowerShell command.
An example of what I'd like to achieve is to simply add that command in the "installation program" field.
Add-WindowsCapability -Online -LimitAccess -Name Tools.Graphics.DirectX~~~~0.0.1.0 -Source .
Currently we have to use this oneliner instead which is far more complex.
Powershell.exe -NoLogo -NoProfile -NonInteractive -Command "Add-WindowsCapability -Name "Tools.Graphics.DirectX~~~~0.0.1.0" -Online -LimitAccess -Source (Get-Location).Path ; if (!$?) { $Host.SetShouldExit($Error[0].Exception.HResult) }"

The ability to right-click a single device, or a device collection and select an option saying "Install Application or Package". This would then allow you to deploy an application or package without having to use a collection, especially if just for one device. It would also allow you to deploy the application or package without needing to build out a deployment for that application. It will just install the selected application or package without any additional configurations needed.

How often do we need to deploy an application to just one machine that is outside of a collection, or deploy to just one machine for immediate testing without having to build a test collection, then add the software to that collection, then run the application requests, wait for it to show up and then deploy. This would speed that up substantially.

1. When deploying an application as available, it will by default be set to UTC time in the scheduling section without the ability to change it to "Client Local Time"
2. When deploying an application as required, it will by default be set to UTC time, unless I check the "installation deadline" then I get the abillity to choose "Client Local Time"

Here in Denmark and other places in Europe UTC is a bit confusing, we always have to be aware of this when deploying applications eg. I want to deploy an application for the end users at 08:00AM then I have to set the deployment time to 10:00AM because of UTC, make no sense for us here in Europe...

I would like to be able to choose "Client Local Time" on all deployment types.

Look at Software Updates deployments, here I can choose "Client Local Time" on both Available and Required, actually it's set by default in our environment.

First off - Thank-you very much for the Email approval in CM 1810.
For the first improvement request, I'd like to request it be able to be sent to Manager or Application / Support owner already identified in the application.

These 3 options would cover nearly every workflow possibility instead of a hardcoded email address.

Usually you require permission from a BA or Business owner of the application, a Technical resource (Helpdesk, etc), or your Supervisor for an application. 2 of these items are already tracked in the application, and the third is (should) populated in AD for the requesting user.

Keep the current single box for 'Installation Program' and ' Uninstall Program' under the 'Programs' tab in a deployment type... however allow admins to select 'granular' switches or arguments.

So in this option, the admin would have:
A 'pre-program install' argument field.
A 'program' field.
And a 'post-program install' argument field.

The same for un-installations.

Additionally to this, I imagine the granular options will have a new window.
This windows should also have a 'explore program' button, which when clicked brings up the potential switches or arguments for EXE / MSI / MSIX / etc. Allowing users to select the options required.

ConfigMgr will then simply populate the original installation / uninstall program field with the one liner, with the full argument.

This will retain the option for admins to either type in, copy paste from another location, or manually select the switches / arguments as needed.