How long should a corporate video be?

As long as the video is interesting and easy to understand people will never feel bored, they may not even notice whether the video is too long or not.
Make sure your video contains all the necessary information using good visuals.

I don’t think you should sit your self a limit.
As long as you change your pace, rhythm, content every 30 seconds.
You can make your ten minute film feel like five minutes with this trick.
Create new "chapters" with new ideas or themes.
Change the music, too.
Your video will be so engaging and will get more views.

The audience will get bored in 10 seconds if your video is monotonous.
5 minutes is the maximum limit, simply because that is enough time for you to say anything you want to.
Keep a balance between good visuals and well spaces voice over segments.

There is no ideal length for corporate videos as long as you know how to fit all the information in a reasonable amount of time.
Make you sure you keep it interesting, appealing and data-centric without it getting boring.
Use the right sound and visual effects to keep it animated and to avoid losing your audience's attention.