It certainly isn't.
But you keep describing it as altered.
I'm the one saying it is not altered in any way.
GOD always had a plan to bless the nations through Abraham/Isaac's descendants.
Christ is not presently on David's throne.
The Scriptures define David's throne as Jerusalem on this earth over the twelve tribes in the land promised.
Ya' might want to read Is 49 again. There's a whole lot more there than the short reference in Acts 13 of GOD blessing the nations.
Hebrews uses the term 'shadows' to pertain to some things but to take license and apply it to prophecy as one chooses willy nilly is out of line. The OT is not 'all' shadows.
If God said the Davidic promises were given to Christ and are in effect now through the mission of the church, then it alters God's word to go back to a Judaic understanding.
The blessing to the nations was not 'through the law.' It appeared so, but that turns out to be the veiled understanding. The blessing and sharing of inheritance and membership is 'through the Gospel' as Eph 3:5 says. That is why it is a mistake to route everything back through anything in the old covenant or scheme.
The devastation that happened to Israel in the 1st century 'fulfilled all that was written' Lk 21. So I suppose you could say Acts 13 is not quite complete by saying that the resurrection of Christ for our justification is the fulfillment of all things promised. Fair point. But there is nothing else besides these two declarations. Anywhere in the NT where the promise of the land might factor in is not there:
1, Rom 4. The promise to Abraham had to do with the whole world
2, Acts 26's hearing. Israel keeps seeking a 'restoration' that Paul says has already come in the resurrection.
3, Heb 11. The believers weren't looking for Israel and they weren't seeking to return to Persia. They were seeking a heavenly place and the promise that one day this world would be renovated.
4, 2 Pet 3. How could it possibly be missing from this chapter? How could Peter have made the mistake of not spelling out Judaic details with TONS of OT prophecy to quote that 'sound' Judaic?
There is no 2P2P in the NT. That is the mistake of trying make the old covenant continue on instead of being set aside as in Heb 8-10. 2P2P folks go into contortions with Hebrews trying to make it say both things. One of the lines goes 'It is only for that generation of Jewish Christians and is about the restoration of the land.' ??? Really? It is quite the opposite. It for all people and anything that is expressed about a restoration is not in Judea but is awaiting above, though very dear, for the Christian believer.
I guess you don't use the NT as the authority of the OT as you should. How do you justify that? If the summary of Paul about isiaah 49 is found in Acts 13, why do we think we 'know more than Paul' about it?
You are not processing what hebrews is saying about the old scheme. Even though Hebrews is the letter that announces a replacement (8:7, 13, 10:9), people have been made to feel guilty about RT regardless. The odd thing about this is that:
1, the real RT problem is that of Gal 3:17
2, we are not replacing anything if Christ was meant all along.
I'm sure you know Hebrews well enough to know that it spends a chapter on the Aaronic priesthood vs Melchizedek. Why? To show that there was already an eternal priesthood before the Law and Moses and Aaron ever arrived. So if Christ was that priest, what is the big deal about dropping it now that it's function is over with?
re the prophets descriptions of the next age:
they had no other tools but the familiar scenes and experiences, but they keep pushing the boundaries to the rest of mankind. This is clarified by statements in the NT, especially Eph 2B-3A. Or the quote of Amos in Acts 15. What they were trying to describe is the living temple of Christ that was reaching the islands and distant shores.