Comparing the -200's performance and the -700's is like comparing the performance of a pair of Ford F-150 pick-up trucks, one with a 250 cu. in. V-6, and the other with a 450 cu. in. V-8 with a supercharger.
The performance of the -700 is so much better than the -200 that you'll rarely see effective restrictions on payload due to runway clutter penalties, or just plane shorter runways.
Westjet is making a good move...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.