Eh. Steen was 11th in goals. They had three players in the top 50 in goal scoring and five in the top 90. They don't have any absolutely elite goalscorers, but of the Cup finalists the last three years, only one team had an elite scorer: Kovalchuk in New Jersey. Even the Hawks, who are incredibly dangerous as a whole, get in the low 20's to the low 30's in goals from their top players, just like the Blues did last year.
As a whole, the Blues take better shots than most teams do. The last two years, they've finished 12th and 3rd in the league in shooting percentage. So, no the Blues don't lack finishers and shooters. Last year, only five teams had more goals: Anaheim, Chicago, Boston, Colorado, and Pittsburgh - and of those, only Anaheim and Pittsburgh have elite goalscorers.
Sure, Steen might be bound for regression, but Stastny adds plenty of offense. If there is any development from Schwartz and Tarasenko (and possibly Lehtera), the Blues will continue to be a top-10 scoring and shooting team. They'll lack an elite scorer, but that's not even common among contending teams right now.
What the Blues truly lack are players who elevate their games in the playoffs.