Igor to me was more an "accurate brawler" similar to Wanderlei but minus the clinch game, Arlovski had his weaknesses but at his peak he threw some incredibly quick and accurate punches plus had the ability to pick away from the outside, both would I think be a problem for Igor.
Its a strange situation really but even as a big fan of Igor back in the day I do think he's an example of what a lot of people incorrectly claim about guys like Fedor, Crocop, etc, the legend has outstripped the reality. You do need to remember of course that Igor was an innovator as well, I class him more like Saku or Bas in that regard rather than judging him against fully evolved MMA of the mid 00's.