Wow !
Excited to learn the new development direction; interested in understand more about IFC types 
As with existing Window Tool, a few earlier quick thoughts:-
- Window with Several Sketches as Base
- Sketch base is fine and simple. Just when sometime when closed loop edges overlap at some part, Sketch fail to return proper Wire.
- If Base accept a list of Sketches instead of only one, each may create a particular window component, there will be more flexibility
With similar concept, using another Sketch with Part Extrude can create a custom opening shape as discussed in Question about custom doors: chamfer, screencapure as shown below.
- Placement of Window
There were several concepts I experimented earlier in my add-on, e.g. (screencapture below) - User-defined Alternative Window Origin
- Currently, the ‘origin’ of the Sketch roughly ‘define’ the origin, or ‘insertion point’ in AutoCAD’s concept
- Just add another placement attribute and user can e.g. use the mid-point of the bottom edge as its ‘origin’ / ‘insertion point’
(more discussion in Intuitive Automatic Windows/Doors + Equipment Placement
- Pre-defined Alignment / Offset from edge e.g.
- Wall Left / Wall Right ( as Left or Right in Align of Wall object)
2. Midpoint, Start, End etc.
Screenshot from 2023-12-21 01-24-54.png