I gave up early on with importing bank statements. Instead I just manually create each gnucash entry for each transaction on my online bank statement. If the final gnucash account balance matches my actual bank balance then I know I did it correctly. If it does not balance, I persist in finding the mistyped entry.

This method relies on balancing to the cent each time, since I use my actual bank balance as the target.

It is indeed tedious at first, however I find that 1) manually entering transactions helps me spot problem payments quickly (comprimised credit card, overcharges on direct debits etc.) and 2) the predictive auto-complete feature speeds entries up over time, as most entries are assigned to either a a)groceries, b)eating-out or c)bills expense account. You just press 'Tab' when the correct suggestion pops-up after entring the first few letter, and the line entry gets auto-filled. I still usually need to change the numerical value, but the correct expense account and transaction detail are prepopulated correctly most of the time.

Overall I would recommend giving it another chance.