I've been mulling over what we where taught in Edinburgh this year and one of the most interesting things (to my mind) was that different senseis had different interpretations of each kata. I've noticed some minor differences before (in the Heian series) but this year some of the differences where quite major.
Example 1. Bassai Dai - the punch-block-punch-block bit close to the start.
Sensei wanted us to punch and then, without really withdrawing the punch hand (and with no reaction hand) use the hip twist to block. Sensei Naito wanted a full blown "punch-hand-back-to-the-shoulder-full-reaction-hand" etc. block. There were other minor differences between Sensei thoughout Bassai Dai.
Example 2. Empi. This time the whole stance was different. The block before the grab and throw at the end of Empi. Sensei taught the block as gedan barai in backstance. Sensei Ochi seemed to teach it as gedan barai in kibadachi stance.
OK I was standing at the back of the class for Ochi's session (pesky kids) so I might have been mistaken - but the majority around me seemed to be in kibadachi stance for the block and could probably see Sensei better than I could !!
Are differences like this common for the more advanced kata? Another interesting this is that Kawasoe Sensei often used bunkai to teach Empi. I've not seen him do this with the Heian katas.