When it comes to clothes designs. I think would be great if it would be impossible to have requested same color clothes as pattern or hemline. Sometimes my designa did not match cause those tiny stars were a pattern and they were same color as actual dress so practially invisible.
Adding more coins for complicated designs would be cool, cause tbh second time around I simply decided not to buy any upgrades for designing just cause it was way easier to quickly make basic clothes aka earn coins, since it was giving same amount of money anyway.