If they are showing something, no matter how many disclaimers they add to it, it has to be somewhat representative of the final product. Otherwise their credibility comes into question.
They kept pointing out that the potencies were not final, but the mechanics were supposedly representative. If this was not the case then every skill that was shown for every class might as well not even be there 2 weeks from now. After all "it's not the final version".


Just as an example: The infamous e3 footage for Gearbox's Aliens Colonial Marines was also said not to be representative of the final version of the game ^^
And in fact it wasn't. Leading to bait and switch remarks, to Gearbox having to deal with a massive backlash and leaving a huge stain in their reputation.