I believe that its a great thing to strive for! It gives the players who dont donate to the Museum some satisfaction and a reward. In all Animal Crossing games I work hard to try and collect all of the golden tools and I really enjoy how much harder some of the tasks are in New Leaf compared to other games. I believe you must completely (?) upgrade the Nookling's store to get the gold shovel! The Rod and Net also have a slower bite rate and bigger radius respectively which makes it SO much easier for me now that I have all the tools! Plus NL made it worth while to keep your silver tools, the shovel can get ore, the axe gives special designs etc. Overall, I really enjoy unlocking the tools in New Leaf and I think the goals are hard but fun!