Maybe I'm missing something obvious here, but can you please clarify what eschatology has to do with who Israel is?
The Kingdom of God is eschatlological, in all aspects, you could say we as co hiers with Christ and thus those who are the blessed nations and in the seed (Abrahamic covenant) of Christ are in this Kingdom, we have Eternal life already but not yet.
The Kingdom of God is described as Already but not yet. it has been innaugurated but awaiting consumation. But you need to see what the Jews where awaiting, they mistakingly thought the Messiah was going to be a sort of earthly King who was going to rid then of oppression. the Messiah wa going to be their King and Israel would be in peace and a light unto the nations. this was their expectation and intertestamental understanding of the Messianic prophecies, they still thought this way as can be seen in Act 1. Jesus then talks them through it and they see it.
When you understand this, the gospels start to come alive...why would Peter say never..to Jesus being smitten on the cross etc. These expectations where at fever pitch when Christ enter victorious into Jerusalem..''Hosanna'.
Yet this is not the Kingdom that Jesus innaugurated, we are now all in the Kingdom of God, both Jew and greek (gentile). we can see the Kingdom at work in the Sermon on the Mount (Kingdom Ethics) and look at all the parables that are similies of the Kingdom...'the Kingdom of God is like....'
That is a very basic talk through, but you get the idea. So the Kingdom is eschatological, our Christian walk is Eschatological. Pauls writings where very eschatological in thought also.
So who fulfilled the promises of Abraham? did not Christ (the Siniatic covenant is fulfilled on all our behalf). and if Christ fulfilled the covenant and we are in Christ? so we are the true Israel the Church.
Now that just leaves one issue. and this is the promise of land to those who are in the promise, i.e all those in Christ?
there are many views, but think of this.
God is through redemptive History reconciling his people to himself, he wants to walk (tabernacle) with his people. First of all in the Garden, God Tabernacles with his peopl (Adam and Eve) then he leads his people to the promised land (yet through rebellion this doesnt work) and then yet to come we have the new earth and the new Jerusalem this is
yet to come.
there where intermediary ways in which God fellowshipped with man:
Tent of meeting
Tabernacle
Temple
Now Christ surpassed all these typologies also.
Well that is just a very quick skim over the eschatological look of scripture, sorry for trying to pack alot into a very small space. I am not trying to convince you either way just my views. to me scripture makes far more sense in redemptive history and to the eschaton than any-other attempt.
in Love
Phil