I don't think that your original model is going to work. The create table will create a new blank table in memory, but you won't have any records for the Calculate Field to update. The Calculate Field tool cannot create new records in the table, so the output would be an empty table that is passed to the Create XY Event tool.
If you wanted this to work in its simplest form you could leverage a RecordSet parameter. This would just require that you provide a schema for the RecordSet. The below model worked for me. The dialog shown is how your users would provide the inputs to the RecordSet parameter. As a result of using the RecordSet users would be able to input multiple points.
If you wanted to expose a variable for the two coordinates (i.e. a Double type parameter for the X_Coord and a Double type parameter for the Y_Coord) without using python you could accomplish this, but you wouldn't be able to use the Create Table tool without using the append tool. I would think that you'd need to have already created a table with a single row. You'd need to copy this table into memory, use calculate field against this to update the already available row, and then create your features from this. I was able to accomplish this with the below model.