I'm gonna have to disagree with most of what you said. While I share you're opinion that the difficulty should have been scaled up, as this was supposed to be the finale to the game, it is my opinion that the way the DLC was excuted was extremely flawed and seems that it is only there as a cash grab for Konami and Mercury Steam and not much else.
If you consider the two levels we got, if the obstacles were taken out, the levels could have been completed in less than 15 mins. Now I'm not saying I want them taken out, they are what make this DLC what they are, add challenge to them and add to the overall experience. The difficulty could have been toned down, or been steady increased over several more levels that should have been added. I didn't think that the platforming was innovative, rather I saw it as taking the more frustrating parts of the game and making them even harder. I was also irritated that Gabriel got no new moves for the combat cross or power for his relics, and that his "transformation" added nothing except him being in pain during a short cut scene.
I think what most people are really upset about however is what this game does to the overall story of Lords of Shadow. In this DLC we were promised a stunning conclusion that showed the fate of Gabriel and the Belmont clan. All we got (or can assume) is that Gabriel fully embraces his dark side becoming Dracula, and that he shattered the combat cross so that we won't be getting 10 sequels of Belmonts (or Alucard, or anyone else for that matter) fighting Dracula. That is also about the only thing that happens. Considering the epilogue to the original game, I think they could have done a better job of setting up a sequel. It would be like if the original game ended after the credits and there were no epilogue. How lame would that have been?
I was really looking forward to a sequel before they released this DLC, but now that they have I feel that they ruined the good story that they had going and I could care less to see a sequel. This DLC raises a lot of new questions, like why doesn't Dracula one-shot Zobek in the epilogue with the Forgotten One's power? Or more importantly, does he lose that power at some point? Obviously he is a lot weaker in the epilogue, so what happened to the badass power that he stole from the Forgotten One.
We all agreed that the price was too much, and it is considering that a $60 game that took 20-25 hours to beat gets DLC that takes less than an hour and together costs a combined total of $20. I think that's a bit steep.
(I should also add that I thought the Forgotten One was laughable and they really should have got a voice actor that was different from the guy that played Cornell.)