If I were the president, I would transform this country into a place that developed high-tech industries.
Even though the "developed" here is in the past tense, it is in a hypothetical sense and is not something really happening in the past.
There is no confusion or ambiguity here.
However, I think this one creates ambiguity:
If I were as hungry as my friend now, I would get the burger he ate.
Is this sentence ambiguous?
I think it's ambiguous because the ate seems to be able to mean both "eat" in the past and would eat.
Without a clear context, the listener might think I would go buy a burger my friend would buy in this hypothetical situation created by the if-clause.
The listener might also think my friend ate a burger sometime in the past and that I would buy the same one if I were as hungry.
By the way:
Can we use the reduced form to still carry the hypothetical meaning?
If I were the president, I would transform this country into a place developing high-tech industries.