Ah yes, Time's Arrow's so uninteresting I had forgotten about it. The original plan of not making it a two parter would probably have been better, and would have spared us all that Mark Twain nonsense.
Birthright is another failed two parter. Not only one of the plots is completely dropped in the second part (Data's dreams), the other one is badly handed. Having Worf dealing with the fact that his father was still alive, but living side by side with his blood enemies in peace, eschewing the so called sacred Klingon ways, would probably have been more interesting. Also it seems to me that the episode takes Worf's side on the matter, justifying the break up of a peaceful community on the account of tradition. Now, this is quite an interesting subject, I just think the episode didn't really approached it well.
Gambit, on the other hand, I find to be quite a fun romp. True, the cliffhanger is weak, but apart from that it injected a heavy dose of adventure and fun in a season that sorely needed it.