has the organizations teaching on the great crowd and other sheep
changed in the last 10 years? are they still interchangeable terms
referring to the same group?
The two terms have never been completely interchangeable inasmuch as 'Other Sheep' includes the faithful living prior to the Christian Era. (e.g. Noah, Moses, Abraham, Sarah, Samuel, etc.)
JW theology holds that Christ opened up a heavenly calling and that from Pentecost clear up until well into the 'Time of the End' that was the only calling. (cf. United In Worship of the Only True God p. 111;) So prior to the 'Time of the End,' 'Other Sheep' simply do not exist in the Christian Era.
In 1935, when the 'Great Crowd' was identified, it was thought that the 'Great Tribulation' had already started, but had been cut short in a manner similar to the relative calm in the eye of a tornado. (i.e. It would start up again shortly.)
There was therefore no equivocation whatsoever about the status of the 'Great Crowd' because it was clear that they had already come out of the 'Great Tribulation.' The terms 'Modern-Day Other Sheep' and 'Great Crowd' were therefore completely synonymous.
In the year 1970, the 'Great Tribulation' was relocated to some indeterminate point in future. (cf. The Watchtower, January 15, 1970 pp. 52-53) This resulted in the demotion of those with the 'Earthly Hope' from actual members of the 'Great Crowd' to only 'Prospective' members of the 'Great Crowd.'
Another upshot of that change is that it became possible for JW's with the 'Earthly Hope' to lose their status as 'Prospective' members of the 'Great Crowd' through accidents, illness and other forms of untimely death and be fully demoted to only, 'Other Sheep.'
However it's one thing for someone with the 'Earthly Hope' to lose their status as a prospective member of the 'Great Crowd' via premature death. It would be quite another thing for JW's to admit that someone with the 'Earthly Hope' was not a prospective member of the 'Great Crowed' even while alive.
As time goes on, this is going to become more and more of a problem which is one possible explanation for why the speaker avoided the term, 'Great Crowd' altogether.