I think your gut instincts are good on this; marriage or not it will not help the waiver.
The CR1 process will take 1 year or more and the Waiver process will take 1 year or more - so lets for the sake of delays, holidays and any forthcoming immigration changes say about 2 or 3 years just for the paper work part and as you said, you don't have definitive hardship... you will find a lawyer willing to take your money but I think you know it wont be successful.
It is hard for me to imagine waiting five years, but I have been away from my husband for 2.5 - every day feels like a year but they have sped by quickly in their own right but we are older and have been married for 5 years before I left. When you consider the years of work ahead of your both without a guarantee there would still be years left to wait if her waiver was denied, you two have some time apart to cope with either way.
Love defies logic, it's' hard to be logical when we feel we cant live being separated from the ones we love but you two have time to really plan this out and to plan it out the correct way and steer each other from making any other lifelong challenges.
Sorry we dont have better news for you or ideas ....
Maybe someone here can tell you how long an approved CR1 stays active - if you two did get married as a means of commitment to each other along with the CR1, having that at the ready might be a good idea. Anything can happen in a year let alone 5 ... you might get a great job offer there!
Just trying to end it on a good note.
Best of luck
