Yes you are perfectly right that it was
ammendment HC321 that brought about the 2 years requirement in
319E of the immigration rules. and also the
HSMP JR guidance states that dependant also qualify.
The question now is, did you have a spouse at the time of initial application? and was there an expectation on your part that she will be granted ILR with you?
I accept that if your spouse was with you before the changes came into effect, then surely they should be covered, there is an expectation on your part that she would be granted ILR. But she never existed during that time, so you could not have held such expectation when you came to the UK.
However, it is could be argued that you held a long term expectation, that when you get married your spouse will be granted ILR at the same time as you. Whether that argument is strong enough remains to be seen.
I accept there may be a case, but it is not clear cut.
I wish you all the best, and also those who may have qualified in the past.