Hi Frosty,
You have some interesting elements going on in your design, like Skinny I'm definitely seeing the arched ceiling, pillars and dome ...
Line-weight variation can add interest and depth, using thick vs thin to emphasise different aspects of a design. At the moment there's a bit of competition and overlap happening with your line weights, which a bit of cleaning up should fix. You could opt for a single line weight to give the design the look of an architectural drawing or isometric sketch... or refine variation to line by considering which parts of the design are 'closest', 'most important' or 'largest' as a way of deciding line thickness.
Naturally, the design and idea has to work for you, so the above are just my 2 cents
Looking forward to seeing more cards
*wave*