Lots of points here, many on which I would like to get some addtional context on before I can respond. I've added my comments below for some but it would be best to sync up over a call to understand this better (sending you a DM to schedule this).
Template Groups, problems with config sync to devices (by the way, the command it was apparently trying to remove is unremovable, fun huh), until VERY recently support for the 7000 series gateways.
<Sunil> Need some context on the config sync issues.
Flexibility of template groups has always been problematic given what the size of the corresponding .json file would have to be. Each site has specific variables and as such we can't use a uniform config and just insert new values.
<Sunil> Template groups and variable files allows for the device configuration to be defined programatically. Parts of the config that vary between sites would be variabalised but you still use the same base template file. This is the flexibility that template groups allow. Let's discuss why this isnt working for you.
We've got config bloat issues with our MAS, headaches with 8.3, and extreme worries about the ability of Central to correctly migrate non-managed devices into the platform.
<Sunil> Need some context on these issues as well.
Managing subscription keys is a nighmare, no improvement to assigning device subscriptions, and this drag/shift-click/control-click thing is an abysmal failure for MSPs.
<Sunil> We now have auto-subscription for MSP as well. Once enabled, devices that are assigned to a tenant will automatically be assigned a DM subscription. Similarly, auto-subscrition can also be enabled for NS subscriptions via the NBAPIs (/licensing/v2/msp/customer/settings/autolicense). This is a one time setting that would assign NS subscriptions to a device when its moved to a tenant.
I can't just tell Central to assign devices automatically as I have over 20,000 devices that were ported (automatically, I might add) from my Activate account, many of which wouldn't even be compatible with Central.
<Sunil> There isnt a workflow to auto assign devices to a tenant so are you referring to auto-subscription? If so, enabling auto-subscription will only subscribe devices that are moved to a tenant and will not subscribe device that are with the MSP itself.