This is my take on wind pants and rain pants:
1. Wind pants aren't very durable. A wind shirt needs reasonable care for snagging on branches, but you sit on pants and there is abrasion from shoes, rocks, and climbing around sticks and logs on the trail. They are in the dirt and mud.
2. Wind pants coordinate well with light running shorts. I think this is the best case scenario for wind pants— a hot weather "height of summer" setup. I wear nylon zip-off hiking pants, which cut the wind in themselves, so wind pants would be redundant. The zip-offs are more durable and are part of my "items worn" list.
3. In my usual hiking climate, if it is windy or cold, it is wet too. Rain pants will cut the wind very well too.
4. As others have written, perspiration is less of an issue with pants. One trick is to get full zip rain pants which can be ventilated at will– with a weight penalty.
5. If you normally take tall gaiters and wear long inseam shorts, you don't have much exposed skin anyway. I've seen many hikers costumed with long johns, long inseam shorts and tall gaiters. Doesn't look good on an REI catalog page, but does the trick on the trail.
6. Rain chaps will work with ponchos or parka-length rain coats and will provide good wind protection— probably one of the lightest multi-purpose leg coverings available (until you sit on a wet log).
I use Golite Reed or Marmot Precip pants. Rain pants with silkweight polyester long johns make for a good cold and wet walking combo rather than trying to wear them over your hiking pants or shorts.
So, IMHO, if you are hiking in hot climates in running shorts and need some occasional protection for your legs, wind pants are worth considering. If you are hiking in wet climates and/or heavy timber, zip-offs and UL rain pants are a better choice.