The thing with the WI is there batsmen are more unpredictable than Pakistan and that takes some doing.
They can be absoluately superb one day and fold to 54 allout the next. The no. of times they have been bowled out for less than 150 is amazing in the last couple of years, but you get batmen like Gayle getting 300+, W.Hinds getting 200+, not to mention Lara, Sarwan, and Chanderpaul.
There bowling is there weakness but there batsmen let them down, time and time again, by just being lazy and not applying themselves.
They lose so many wickets to the new ball it is amazing, probably stats will show that Chanderpaul finds himself at 30-3 more often than Inzy does for Pakistan.
It just depends on the day which batting line up turns up on the day. Pakistan should not be over confident, but bowling a good containing line and length backed up by good fielding and good field placements, will put the west indies batsmen under severe pressure, and they are more likely than not likely to self capitulate.