Several things should be added in-client.
A feedback dialogue.
The event schedule.
An easy card viewer that doesn't require me to open a deck.

The deckbuilder is tedious. I should be able to save several versions of my limited deck and it shouldn't take 40 individual clicks to clear the deck.

The limited event rewards seem arbitrary and are frustrating as the negative swings are much higher than the positive ones.
Losing to your own cards isn't fun...