Having filmed the Makarova version of La Bayadere (also viewing it and the RB/La Scala versions several times), and particpated in interviews with Ms. Makarova where she described her reasoning for including some dramatic actions and especially a last act (I may edit this later to include her quotes), I can say that...
1) There is a specific moment where Nikiya points an accusing finger at Gamzatti after being bitten by the snake, and a reaction by Gamzatti (though the reaction--either feigned shock that Nikiya dared accuse her, contempt, or nervous guilt--depended on who performed the role) and Solor to this news.
2) Nikiya doesn't take the antidote because, when she looks to Solor, he is walking away with Gamzatti (after a surreptitious unhappy/guilty look back at Nikiya--which neither she nor Gamzatti see), so defeated and heartbroken Nikiya lets the poison kill her.
3) In the last scene of the Shades act, Solor awakes to find that Gamzatti and entourage have arrived at his door and she proceeds to stalk slowly towards him as he slowly tries to back away and then stops. A literal/physical exemplification of Gamzatti's power and ability to force him to face her & her intentions.
4) There is a moment in the final act (I think after the 'candle dance' but before the PDQ) in which Gamzatti has a solo that expresses both her yearning for Solor and frustration/rage, while the other protagonists remain 'frozen' in place. A sort of dance soliloquoy on her part.
5) Nikiya's ghost is present at the wedding to remind Solor that he made a vow to her on the sacred flame; to confront Gamzatti through the use of a flowergirl who offers a similarly suspicious basket, and by G's horrified reaction, so demonstrate Gamzatti's guilt; and to show her (Nikiya's) continuing love for Solor.
6) There is also a point where the priest literally forces Solor to kneel on the alter--so it is literally a forced marriage in all ways.
7) Finally, the gods wreak vengeance on the wedding party because they (Rajah, priest, Gamzatti et.al.)murdered their Bayadere/temple girl. Nikiya's ghost is just the messenger. That Solor also dies, is a prize for Nikiya who can now lead him to 'the promised land/level/ring of heaven/nirvana/cloud9 whatever to enjoy a happier afterlife.
Just some observations of a rather convoluted plot, but luckily with some great footage and dancer-actors to demonstrate its nuances of motivation.
Thanks for all the info. That helps make the wedding as sad understandable. Overall I do love Makarova's version of Bayadere. I think the only wish I have is that she could have kept the Shades at 32, but I read that the Met's stage could only hold 24. When you watch versions with 32 it seems to go on forever and is mesmerizing! But I guess 24 Shades all in synch is pretty amazing too, so I can't really complain.