Academic studies over the last decade have pointed out that the legal architecture of Member States is an important predictor of their success in transposing EU legislation. Due to peculiarities in the structure of their national legal order, some Member States have become ‘legal misfits’ and been penalised by the EU. With Member States’ limited influence over how requirements of a directive need to be included or elaborated and lack of possibilities to opt out, what mechanisms should the EU put into place to ensure legal fit of its Member States into union-wide legislation?