Its an interesting period with many new tactics, and much more ofcouse :D
But the best would have been a TW game focused on the Broken Crescnent theme, as the armies of the east dont just look exotic but also much better than european armies, also horse archery was common the, pro and con, pro: cool battle con: AI will be difficult to set up to handle HA, also I think cities of that area in that time were far better developed and less poor.
If you want to know my reason check out BC, history books on middle eastern warfare, and google :D