I've often thought the same thing, i love cooking but find it hard to decide what to cook based on the ingredients i have and i end up making the same thing every time

I would be happy with recipes that say "You would need to buy: X" so if i have 75% of the ingredients i can decide whether to go and shop or not

And regarding the items in stock, what about a wizard based filter that asks what you have, so you would input the main ingredients you have i.e. Onion, Chicken, Pasta, then it would ask Do you have Cream? Yes/no, Do you have Mushrooms, Yes/No, logging these every time to improve the understanding of your larder. It could even ask "Do you still have Mushrooms" if you said yes a day or two ago. It could then make suggestions based on what you have, with a small shopping list to make something else