I've run this new flashpoint three times so far, yet I still struggle to express my opinion on it. I feel that it's a solid piece of content, but I'm having a hard time getting really excited about it. It's supposed to be the second of (I think) three parts of the Forged Alliances story, and based on previous experience, I often find the middle part of a trilogy a bit lacklustre, as it provides neither the excitement of setting up a new story arc nor the satisfaction of a proper conclusion. I was surprised to hear people like JD praise it for supposedly being so much better and more engaging than the first part.
(Story spoilers in this paragraph only.) Finding out that Colonel Darok and Darth Arkous are working together probably comes as a surprise to exactly no-one, considering that this is exactly what the ending of part one was hinting at. That they were trying to create a new type of supersoldier is hardly a shock either. (They were bound to be planning something to gain power.) The revelation that they are working for the Revanites was certainly interesting, but considering that Lana then says that they have changed a lot since those early quests on Dromund Kaas, we don't really know what facing the Revanites means, leaving us no wiser about what to expect of this new enemy than we were before. Bring on part three already, is all I'm saying.
As for Manaan, I got the impression that a lot of people were very excited about it simply because it's a planet that was previously featured in the original Knights of the Old Republic game. As someone who still hasn't played either KOTOR and was therefore lacking this emotional connection, I honestly found the area kind of bland and clinical looking. Though the signs were funny I guess. "We also kindly ask that you do not swim or bathe in plaza fountains." Also, water that is more than knee-deep! Of course you die if you jump into the sea. (Once again, I just had to try.) I guess it doesn't matter if you're the best of the best of Republic special forces or a Sith of the Dark Council, the ability to swim is just too much to ask.
In general I approve of Bioware letting us go down on the planet before entering the flashpoint though, even if there isn't anything more to it right now than the welcoming area. There is always room to add more content in the future. And I do like the music that plays there. The moment I first heard it, it immediately made me think of wide, open sea.
Mechanics-wise the new flashpoint is pretty entertaining. There isn't too much trash, and the bosses actually require you to pay some attention. On our first run-through my pet tank and I decided to duo the instance once again, but even with how overgeared we were, we felt pushed to our limits on some fights. The last boss even seems to have a five minute enrage timer (or rather, you keep getting the message that you'll die if you don't beat him within five minutes; I haven't tested it but I assume it's true). The two of us with two dps companions out barely got him down in time. When we later pugged a run with a full group, another guy managed to get himself killed within seconds on the second boss by standing in "the bad", as it really was that deadly. We'll see how long it takes until they nerf that I guess.
If you haven't caught up with the Forged Alliances story yet, I highly recommend it! I'm just glad we shouldn't have to wait very long until the release of part three, which will hopefully include some genuinely new information.