I have made kilts of a whole lot of different fabrics; many weights and weavers of wool, 2 weights and weavers of poly/viscose, many different hemps, polyesters, etc.
I made all these different kinds of kilts but the only fabrics I found I wanted to make and sell kilts with were wool and poly/viscose.
Speaking as one of the few people around who has actually made and worn both wool and poly/viscose kilts for a couple of years, I can tell you straight that there is little difference in making a wool or poly/viscose kilt. There is some difference in the fabric's ability to be stretched into shape. (Wool is better here.)
After two and a half years of wearing these kilts, I have never worn out a kilt. I've never seen the weave come loose, nor have any of my customers mentioned it.
The advantages of a wool kilt is that the fabric swings better and it is the traditional material used for kilts. Until we have poly/viscose kilts that are decades old, we won't know about the wear. Though Andrew is stress testing one with his hikes.
If kilts were a new style of garment just invented, which fabric would be chosen? Try to make this choice without thinking 'tradition.'