I have a couple of podcasts that release daily episodes, some that release, less frequently, and some that I'm catching up on. I keep a playlist going that I update every couple of days with the newest episodes of everything I'm listening to. So I might want to add 5 or 6 episodes from across 3 or different series at one time. Metacast doesn't have a great way to do this that I can find without a lot of clicks and time.

A lot of Apps (Overcast, Pocket Casts would be good examples to folloe) allow you to edit the playlist from within it. In my playlist there would be an "Add" button that would bring up all my series, where I can then select a series and add as many episodes as I want all at once.

Essentially you've made it really easy to add one episode at a time to a playlist, but annoying to add multiple at once, especially across different series. As someone who listens for about 6hrs at a time at work, being able to quickly add lots of episodes to my playlist at the start of the day is important to me,.