In my case I wish to add three options to shipping:-
Free Economy
Standard
Express.
Notes to above, predominantly Royal Mail large letter size with a sprinkling of small parcels and the odd one over a kilo. I use 2nd class free, 1st class standard and Special delivery express moving to carrier services for weights normally above 1kg.
Royal mail is complex with odd and large breaks making any system not using their rate tables nigh on impossible to cater for.
Based on that I cannot use your product to plug all. I cannot use Woocommerce rates to solve all either. But with a little thinking using a minimum handling fee and rate per kilo for express, your product is under my minimum cost rate by 8p, 25p over on the 1kg rate and spot on on the 2kg rate with mixed blessing in between. So for plugging one hole I am very happy.
To improve this product from my personal perspective (accepting everyone has a different problem to solve) at its simplest, you would need to duplicate what you have a number of times (or be able to enable as needed). This way at least your rate system could be used for different catagories in my case perhaps 1st and 2nd class and my existing express.
AWD which I also use allows you to set a weight, price and group but is also far more complex to set up at the start.
Hope this gets your thought flowing ;o)