Westjet had originally planned to get 6 new planes this year, but with the cancellations at Boeing after Sept 11, Boeing made them a deal they couldn't refuse, hence the extra aircraft. Even if they do not have any new routes, they will retire the -200s early because the -700 is more economical to operate.
The airport security levy is not a major issue to travelers, it is the increased time through security. By the time you have finished waiting in line, you could have already driven to some short-haul destinations.
The interesting thing about the levy is that it was decided on solely by the finance department. Transport Canada has no idea yet how this money will be spent. Also, there will be no way to track it because it will go into general coffers and not a dedicated account.