There are 106 new cmdlets in ConfigMgr, below you find the complete list:
Totally need to look into the New-CMTSStep* cmdlets for OSD. But here is a sneak preview on editing a Run Command Line action in a task sequence
Set-CMTSStepRunCommandLine -CommandLine "PowerShell.exe -ExecutionPolicy ByPass -File ShinyBitLockerScript.ps1" `
-PackageId "TP100012" -TaskSequenceName "POSH Test" -StepName "Enable BitLocker"

Editing task sequence steps via PowerShell.
The new ConfigMgr TP 1705 cmdlets (compared with TP 1704)
Get-CMTSStepInstallApplication
Get-CMTSStepInstallSoftware
Get-CMTSStepReboot
Get-CMTSStepRunCommandLine
Get-CMTSStepSetVariable
Remove-CMTSStepInstallApplication
Remove-CMTSStepInstallSoftware
Remove-CMTSStepReboot
Remove-CMTSStepRunCommandLine
Remove-CMTSStepSetVariable
Add-CMComplianceSettingActiveDirectoryQuery
Add-CMComplianceSettingAssembly
Add-CMComplianceSettingDirectory
Add-CMComplianceSettingFile
Add-CMComplianceSettingIisMetabase
Add-CMComplianceSettingRegistryKey
Add-CMComplianceSettingRegistryKeyValue
Add-CMComplianceSettingRule
Add-CMComplianceSettingScript
Add-CMComplianceSettingSqlQuery
Add-CMComplianceSettingWqlQuery
Add-CMComplianceSettingXPathQuery
Add-CMTaskSequenceStep
Enable-CMSiteFeature
Get-CMComplianceRule
Get-CMComplianceSetting
Get-CMSiteFeature
Get-CMSiteUpdate
Get-CMSiteUpdateHistory
Get-CMSiteUpdateInstallStatus
Get-CMTaskSequenceGroup
Get-CMTaskSequenceStep
Get-CMTaskSequenceStepCondition
Get-CMTSStepConditionFile
Get-CMTSStepConditionFolder
Get-CMTSStepConditionIfStatement
Get-CMTSStepConditionOperatingSystem
Get-CMTSStepConditionQueryWmi
Get-CMTSStepConditionRegistry
Get-CMTSStepConditionSoftware
Get-CMTSStepConditionVariable
Install-CMSiteUpdate
Invoke-CMSitePromotePreproductionClient
Invoke-CMSiteUpdateCheck
Invoke-CMSiteUpdateDownload
Invoke-CMSiteUpdatePrerequisiteCheck
New-CMComplianceRuleAssembly
New-CMComplianceRuleExistential
New-CMComplianceRuleFileFolderAttribute
New-CMComplianceRuleFileFolderDate
New-CMComplianceRuleFileFolderPermission
New-CMComplianceRuleFileFolderSimple
New-CMComplianceRuleFileFolderSize
New-CMComplianceRuleRegistryKeyPermission
New-CMComplianceRuleValue
New-CMComplianceRuleVersion
New-CMDetectionClauseDirectory
New-CMDetectionClauseFile
New-CMDetectionClauseMacBundle
New-CMDetectionClauseMacPackage
New-CMDetectionClauseRegistryKey
New-CMDetectionClauseRegistryKeyValue
New-CMDetectionClauseWindowsInstaller
New-CMTaskSequenceGroup
New-CMTSStepConditionFile
New-CMTSStepConditionFolder
New-CMTSStepConditionIfStatement
New-CMTSStepConditionOperatingSystem
New-CMTSStepConditionQueryWmi
New-CMTSStepConditionRegistry
New-CMTSStepConditionSoftware
New-CMTSStepConditionVariable
New-CMTSStepInstallApplication
New-CMTSStepInstallSoftware
New-CMTSStepReboot
New-CMTSStepRunCommandLine
New-CMTSStepSetVariable
Remove-CMComplianceRule
Remove-CMComplianceSetting
Remove-CMTaskSequenceGroup
Remove-CMTaskSequenceStep
Set-CMComplianceRuleAssembly
Set-CMComplianceRuleExistential
Set-CMComplianceRuleFileFolderAttribute
Set-CMComplianceRuleFileFolderDate
Set-CMComplianceRuleFileFolderPermission
Set-CMComplianceRuleFileFolderSimple
Set-CMComplianceRuleFileFolderSize
Set-CMComplianceRuleRegistryKeyPermission
Set-CMComplianceRuleValue
Set-CMComplianceRuleVersion
Set-CMComplianceSettingActiveDirectoryQuery
Set-CMComplianceSettingAssembly
Set-CMComplianceSettingDirectory
Set-CMComplianceSettingFile
Set-CMComplianceSettingIisMetabase
Set-CMComplianceSettingRegistryKey
Set-CMComplianceSettingRegistryKeyValue
Set-CMComplianceSettingScript
Set-CMComplianceSettingSqlQuery
Set-CMComplianceSettingWqlQuery
Set-CMComplianceSettingXPathQuery
Set-CMTaskSequenceGroup
Set-CMTSStepInstallApplication
Set-CMTSStepInstallSoftware
Set-CMTSStepReboot
Set-CMTSStepRunCommandLine
Set-CMTSStepSetVariable
Add-CMComplianceRegistrySetting
New-CMComplianceRule
Written by Johan Arwidmark