We fly WestJet several times per year and never had issues with them. They have switched our flights twice. Once was about a week ahead of the flight due to scheduling changes, but I called to tell them it was unacceptable (overnight layover, flight arrived too late) and they found a different route for us, no additional charge, and it was better than the original flights we had. People need to realize they can call and mention these things - it even says so on their flight change notification email. The person I talked to had three or four different options for me to choose from, and their system automatically selects one, but if you talk to a person you'll likely have other options.
They have stopped carrying EpiPens onboard as of October 2015, though the syringes and phials of epinephrine are still stocked in their first aid kit. I don't know the reason why - I suspect lack of use and expense to track and replace. Their allergy policies haven't changed otherwise.
We did have one flight that was delayed coming home because of mechanical failure on the original plane, forcing them to prepare another plane for us, delaying the flight about two hours. They gave us each a $50 credit without even asking for it. (I actually had to call and ask why I had an email with a $50 credit for troubles with a recent flight because I didn't think that was that troublesome and never complained. It was an automatic thing they do for certain delays. We eventually got to fly on the Mickey Mouse plane... so I was happy.)
I'm really hoping they haven't let their service slide in the past few months. But Christmas season can be a troublesome time to fly with any airline because it's so busy everywhere.