Metastability isnt the same problem as it used to be with older devices and I have never seen a design display metastability which hasnt been flagged by modelsim as setup and hold violations.
Of course you can go from a functional sim straight to place and route without seeing any problems and thats because you havent done the backanotated gate level sim with the vital timing model,so its the same as with any other tool you have to know what you are doing.