I want to override/manupulate a Shopify core function. There is no way to do this with the admin api, so I came across "Shopify Functions". "Shopify Functions" does not offer many possibilities, so my question: would there be more possibilities / functions soon? Specifically, I want to manipulate the customer registration process so that I validate for additional stuff server-side. As a developer, can I request this Shopify function in the short term? Respectively, what would be the procedure here?
The slack channel is not intended specifically for feature requests, but you can join the channel related to Shopify Functions and connect with other members of the Shopify developer community as well as product managers and engineers involved in the various partner-facing products you are working with.
As you may be aware, Functions are essentially brand new and around half of the existing APIs are still in beta (developer preview). Once a new Function API has been published to a developer preview mode, you may be able to get early access granted for a merchant store, but it depends heavily on the API, the merchant and the use case. With that in mind I wouldn't expect to see the feature you're hoping for in production any time in the next year unless the product team already happened to be working on it.
Out of curiosity, what are you hoping to accomplish with customer accounts that isn't possible with the admin API? I wonder if it's possible to combine the storefront API with admin API to accomplish your goal. For example you could try using the storefront API to create the customer after performing your server-side validations and see where that gets you.