Based on their Hero Charts (which doesn't tell the whole story) this is a huge win for the Capitals.
Oshie:
http://public.tableau.com/shared/DFS...play_count=yes
Brouwer:
http://public.tableau.com/shared/7HX...play_count=yes
Neither have been good playoff performers (both have actually been pretty disappointing).
Brouwer might be better suited to a 3rd line role than Oshie though, and might be a tad better defensively.