Why did the crust get too hard on my Blueberry Cheesecake?
Your ratio of butter to cookie is probably the main problem here: using too much butter and refrigerating it overnight will give your crust the texture of... well... refrigerated butter.

So, change the recipe and use one of the following options:


Lightly soak the cookies in coffee/tea/lemonade/Cognac/whatever liquid is to your taste.
Use less volume of butter and add the same volume of cookies.
Powder the cookies in a blender
Use a mixture of oil and butter (take one with a neutral taste like grape-seed oil).  Test out a few spoonfuls in some shot glasses (50/50, 60/40, ... until you get the texture you want) 


You can also combine the above, but that would be riskier: change one parameter at a time...

Can I have a piece of that perfect blueberry cheesecake now? :-)