Rich, he played four matches against Bangladesh, and one against Zimbabwe. That's five tests from 40, which is not a disproportionate ratio of matches vs minnows for any player these days.
I don't see how the wickets he took in the ICC XI match don't count. In that match he dismissed: Sehwag, Inzi, Flintoff (twice), Vettori, Harmison (twice), Murali (twice). Apart from Inzi, none of them are really great batsmen, but Sehwag, Inzi, Flintoff, and Vettori at least are no slouches. Maybe they weren't fully engaged in the match, but I don't see why they shouldn't be counted towards his record - they're at least as "test standard" as the wicket of tail-enders in normal test teams, or of poor batsmen who are in test teams.
The only countries who have had consistent success against him are India and Sri Lanka: and they have probably the best batting line ups against spin, and MacGill isn't unique in struggling against them. His records against England, South Africa, Pakistan and the West Indies, are certainly very good. He's only gone wicketless in one test match. He's averaged well under 30 in a batsman friendly era - no mean feat for a spinner, particularly one who is as attacking as he is (he's much more of a Mailey style millionaire than a Grimmitt style miser). And I'd say rather than having the "luxury" of being dropped after a couple of bad games, he's shown remarkable resiliance in consistently serving as an understudy but producing the goods when he gets a chance.
As far as I'm concerned, that World XI match should not have been a Test-match. Therefore, I refuse to take anything which happened in it as a Test. Just because he got good players out does not mean anything - he could bowl at WA or Qld and he'd be bowling at plenty of good players, but it doesn't mean such games should be classed Tests. Hussey, Campbell, Langer, Katich, Goodwin, Martyn, Gilchrist... hardly a shabby side... or Maher, Hayden, Love, Law, Symonds, Haddin, Hopes, Bichel... (all right I'm going back a few years in both line-ups, but you get the picture).
And I'll take a tour through MacGill's proper Tests... (I have done this before, but I can't find the post
)
36 8 134 5 3.72 D 3rd Test v SA in Aus 1997/98 at Adelaide - looks good, but it was actually not great, just got 3 wickets when SA were going for a declaration, which happens again later...
43 12 113 9 2.62 W 1st Test v Pak in Pak 1998/99 at Rawalpindi - excellent
42 5 169 2 4.02 D 2nd Test v Pak in Pak 1998/99 at Peshawar - very poor
42.4 7 130 4 3.04 D 3rd Test v Pak in Pak 1998/99 at Karachi - reasonable enough
46 7 121 4 2.63 D 1st Test v Eng in Aus 1998/99 at Brisbane - reasonable enough
53 14 108 4 2.03 W 3rd Test v Eng in Aus 1998/99 at Adelaide - reasonable enough
46 5 142 7 3.08 L 4th Test v Eng in Aus 1998/99 at Melbourne - superb
40.2 6 107 12 2.65 W 5th Test v Eng in Aus 1998/99 at Sydney - magnificent
16 5 41 3 2.56 W 1st Test v WI in WI 1998/99 at Port of Spain - very good
22.3 3 84 3 3.73 L 2nd Test v WI in WI 1998/99 at Kingston - reasonable enough
41 11 95 1 2.31 L 3rd Test v WI in WI 1998/99 at Bridgetown - very poor
40 11 132 5 3.30 W 4th Test v WI in WI 1998/99 at St John's - pretty good
21 6 52 3 2.47 W 1st Test v WI in Aus 2000/01 at Brisbane - very good
32 8 84 4 2.62 W 2nd Test v WI in Aus 2000/01 at Perth - very good
36 7 173 2 4.80 W 3rd Test v WI in Aus 2000/01 at Adelaide - very poor
67 18 192 7 2.86 W 5th Test v WI in Aus 2000/01 at Sydney - reasonable enough
65.2 19 174 7 2.66 W 3rd Test v SA in Aus 2001/02 at Sydney - pretty good
84 20 260 7 3.09 W 4th Test v Eng in Aus 2002/03 at Melbourne - very poor
85 16 226 5 2.65 L 5th Test v Eng in Aus 2002/03 at Sydney - very poor
43 9 189 5 4.39 W 1st Test v WI in WI 2002/03 at Georgetown - poor
47 10 151 4 3.21 W 2nd Test v WI in WI 2002/03 at Port of Spain - very poor
75.5 19 182 9 2.40 W 3rd Test v WI in WI 2002/03 at Bridgetown - excellent
38.2 8 156 2 4.06 L 4th Test v WI in WI 2002/03 at St John's - very poor
30.1 4 118 4 3.91 D 1st Test v Ind in Aus 2003/04 at Brisbane - looks good, but had a tailender boost
68.4 11 244 4 3.55 L 2nd Test v Ind in Aus 2003/04 at Adelaide - very poor
41.5 8 138 5 3.29 W 3rd Test v Ind in Aus 2003/04 at Melbourne - reasonable enough
54 6 211 1 3.90 D 4th Test v Ind in Aus 2003/04 at Sydney - very poor
38.2 6 143 5 3.73 W 1st Test v SL in SL 2003/04 at Galle - reasonable enough
17 1 89 0 5.23 W 2nd Test v SL in SL 2003/04 at Kandy - very poor
47 7 170 8 3.61 W 3rd Test v Pak in Aus 2004/05 at Sydney - excellent
37 7 87 5 2.35 W 2nd Test v WI in Aus 2005/06 at Hobart - excellent
29 5 102 2 3.51 W 3rd Test v WI in Aus 2005/06 at Adelaide - very poor
31 10 69 2 2.22 W 2nd Test v SA in Aus 2005/06 at Melbourne - poor
35 6 135 4 3.85 W 3rd Test v SA in Aus 2005/06 at Sydney - virtually a repeat of his debut
You see? There's really not that many particularly good games in there - that's 11 good ones, 6 reasonable and 16 to-varying-degrees poor ones. Now, this is certainly not the record of an out-and-out poor bowler, but nor is it one of an especially good one, which some claim MacGill to be. And especially when you consider that far more of the good games than not were quite a while ago now, and often against downtrodden sides (England at The MCG and SCG 1998\99, WI at The Gabba and WACA 2000\01).
I'd certainly dispute that his record against England is good - it's not bad, certainly, but it's not as good as some would have it (2 reasonable to start, 2 excellent in the middle and 2 bad to finish). I'd most certainly dispute that his record against SA and Pak is good, given that he's only played 3 and 4 Tests respectibly (for, respectively, 1 good and 2 poor; and 2 good and 2 poor). Against West Indies, it's often been a case of if they can get on top of him they play him well, if they can't he often cashes-in.
And I most certainly do feel that had Warne, say, taken-up Aussie Rules at 15 (and had success) MacGill's Test career would be longer and less impressive.