If you've got new techniques up your sleeve, go ahead and use them. I will say that I personally am very happy with the existing ANH you've made. But then again, I don't pick up on the problems most people do. So it's really up to you. If you feel unsatisfied, give it another go. If you feel it's good enough, then put it on hold. I might add that if you do decide to redo ANH, I hope you would do so after you've completed ESB and ROTJ. But those are simply my personal feelings. Again, good job on what you've already done!