"If you had a blank sheet of paper what would be your ideal solution to the challenges we're discussing?"
Few questions strike at the heart of the matter like this one. Quite simply, it reveals exactly what your buyer wants so you can help them get it.
It demonstrates your desire to get as close to their perfect solution as possible, and that you are willing to tailor your solution and not just offer something off-the-shelf.
It may just reveal something you have missed and elevate you above your competitors, particularly if you have the flexibility to customise your solution.
Far too many sales conversations are more akin to square peg/round hole or throwing far too much at the wall to see what sticks.
Personally, whenever I buy something, if there is no personalisation or I feel there is no desire to meet my specific needs, I will just shop around till I find it. I don't want something off-the-shelf - I want something special where the salesperson seems to really care and puts in the effort to secure me as a new customer.