Technically they shouldn't even use cardinal directions for QEW at this junction.I bet the majority of those on 400 heading west also only go a short distance - to 409 or 427. An airport symbol would help too.
Also heading the junction to the west is the 30 ... which one could take all the way to Sorel (unlikely) or to other south-shore destinations (quite likely for those that live near the 40 in Vaudreuil - or even at the very west of the island; heading down Decarie or the 13 and 20 to the Champlain Bridge is often too busy.
Bottom line, is that I agree that the signage to 400/401 is insufficient.
There's other gems around here; most people wanting to get downtown, surely go to the middle, when they should go to the right - which leads to both the QEW East AND West.
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