I was envisioning having armpit zippers on the jacket to allow air if you get too hot. I had a jacket a while back with this feature and it was really great. As far as being flexible I think the liner actually helps in multiple weather conditions. The fact that it wicks moisture means that in cool conditions when you stop moving you will remain dry and not suffer coldness from the breeze and with the armpit zippers you will have the option to cool off if things are getting too warm. Could be a personal preference, but with my experience the lining has been great in the past and something I would like to incorporate into the jacket I'll be making.