McIntyre's best seasonal average was 32.75, in 1992/93. In 1994/95, the season he was picked against England in, he took 40 at 34.95, which is better than his standard, but still hardly stuff that screams "TEST MATERIAL" IMO. As for England being bad players of wristspin, well that was always something of a myth - truth was England were bad against high-quality wristspin (such as Warne) but against moderate wristspin they like most people would cash-in and sure enough, the top-order played McIntyre with no difficulty (his only wickets were that noted batsman Phillip DeFreitas and the last wicket of the innings which was Mike Gatting hitting-out).
As for the one-off game in India in 1996/97, I've never been totally sure who else was going around in terms of spin at the time - the fact that he and Hogg were the spinners of choice suggests not very much (MacGill had played 1 First-Class game 3 years ago for instance, and would only get into the Shield properly the Australian season which followed that one-off Test). But it seems odd that, with Warne injured, two spinners were picked.
Even though it was almost unheard of to have all of McDermott, Reiffel, Fleming, McGrath, Gillespie and Kasprowicz fit and having established their credentials at the same time, I can't believe there was very often a time when 3 of them weren't available and proven.