We are building Phoenix Point to have mod support, although it won't be there at launch. I can't say for certain if it will be via the Steam Workshop or not, as we are also releasing on GOG.
I have to say thanks for that.
There are users in other platforms that aren't Steam so a solution that is not tied with it is something to say thanks since sometime this kind of features aren't available for them.
The ideal, I think, it should be use the steam workshop for users than want to use it but also have other solution for platforms or users that can't or don't want to use the steam workshop.
The problem, more work to maintain those extra systems.
And just in case, I don't have any problem with Steam (I'm a looong time user of it), but I also have accounts in other services and I've seen this kind of issue happen before.