Simple Video Edit features - Cannot trim anymore

The product team is working on two solutions at the same time for this and we are hoping to see them both show up before the end of the year. The first is similar to what you are saying you have to do now - use Microsoft Clipchamp. (It is in Preview as an Enterprise app and is expected to roll out GA by the end of the year.) The second is they are working on adding a "hide" feature that uses metadata to hide content anywhere within the video - but it doesn't literally cut anything out of the file. This will allow you to "trim" or "hide" as many sections of the video as you want to. This is in development and hopefully will also roll out by the end of the year.

Per the Stream product team, their analytics didn't indicate that Trim was used that much. However, it is the most frequently asked question to the team on migration calls and they are working on it. The development just isn't going as fast as we would like it to.