Ellison (1982) translates the word as “I shall be that (what) I shall be.” This is quite different to the normal translation of “I am who I am.” “I am who I am” places an emphasis on here and now. God is who he is and we shouldn't question it. Ellison's translation presents an interesting challenge. “I shall be that (what) I shall be” is giving a future tense to God's name. It is looking forward to what God will do and accomplish for his people.
In the context of this passage (Exodus 6:2-27), it is this future hope that the people of Israel need to trust in. They and their forbearers have received promises that have remained unfulfilled. Now the people are forced labour under the Egyptians. This surely isn't the fulfilment of the promise of being God's people. There would seem to be valid reasons for disappointment in God and being called “I am who I am” wouldn't carry a great message of hope.
But “I shall be that (what) I shall be” is forward looking. It is raising the possibility that God will act and restore hope for his people.
As I write this, I am coming to the end of the writing of my PhD and although I have applied for positions, nothing has materialised as a job offer. It isn't the first time in my life that a change in direction in my career has occurred. Last time, it felt like all that I had worked for and done counted for nothing. Industry said that I could not change from being a mainframe programmer to programming PCs. This was despite having just moved into supporting IBM AS400s. Now, the message from industry is that I don't have enough current experience of the technologies and that I am over qualified for a position that would enable me to get up to speed with the technologies.
Trust in man give me no confidence but trust in a god who will be what he will be gives me hope. His plan and promise will be worked out even if I can't see it yet. I simply need to place my trust in him.
Ellison, H. L. (1982). Exodus. Edinburgh: The Saint Andrews Press.