That is all and well, but you're not the OP and he might find other approaches viable. And furthermore, your tactic is viable starting from 13th lvl which is pretty damn far, considering the fact that they're starting at first lvl.

Also, note that some DMs (me, for example) won't allow you to take Multiattack/Improved Natural Attack because they have prerequsites to have natural attacks, which you don't, in your natural form. Better check it with your DM first.