Then you should have no problem with Christianity.
The finished prophecy, something you yourself admitted to in your previous post, involved his resurrection. It is finished was the acknowledgment that Jesus had done his part, and with that, the prophecy and scripture had been fulfilled. Then it was God's turn to finish, bringing him back to his followers to begin the new Church.
As far as the prophets after Christ, of course God spoke to them, the story itself needed to be complete, the record finalized, the lesson of Christ love set to be shared with the world and the end of days revealed. That is why we have the written books that came after the Gospel. So if your theory is correct, then why do we have the letters of Paul, why do we have the Revelation. You have said that the Word died with Christ. Well let's say it did not, lets say it dies a little later. The LDS quotes Paul, who wrote letters to bands of Christians whose linage can be tracked to the present, the historical places are well known (more than can be said for the places in the BOM) we even know of some of the caves they first met in. If the word dies before Paul could get it out, then why even refer to it? By your standard it is in error to do so.
Paul and the other prophets we not totally rejected, we still use their works today. Those interested in destroying the nascent church did not like them and saw them as enemies, but the faithful never did. In time their spirit won out.
God calls and has called many through out history. There have been great men, and women, of God who have answered Christ's call for 2000 years. Just because we do not keep making the Bible larger and larger does not mean that scripture is not being written in the hearts of the faithful, that lessons are still not being taught, but again God has turned that job over to us, who, like you said yourself, hear God's words.
There has been no true"dark ages" for the faithful. Yes the evil one has sought his revenge daily using the Church as a battle ground, seeking to divide, seeking to start fights, and among leaders both religious and political he has found souls easy to influence, and has create certainly some dark hours and events. With time we have separated over issues of liturgical value, certain beliefs and practices due to his influences, but one common theme is shared amongst us all, the Grace and power of the Lord through his son Jesus.
I know it would be of benefit to the desires of the LDS to have a heavily divided Christian faith, it would be a self fulfilling "prophecy" that could lend at least some credence to the words of your Prophets. Sadly, no such divide really exists, the differences fall to trivialities amongst the faithful when the sum total is taken into account.
If indeed we were all enemies and believed (knew) differently from each other, as an Orthodox Christian going to a Methodist church I could not sit down at a table at a Prison Ministry meeting with a Catholic, and Episcopal Priest from Africa, a Baptist Preacher, a Presbyterian and another Methodist and share a meal and discuss God's unending grace as one family. Indeed none of us could be there without the blessing of our individual faith's authorities, who do indeed bless and support this, and other such, ecumenical ministries.
You seek problems where none exist, in an effort to solve problems that can never be resolved, a fruitless pursuit.