I downloaded the trials for several movie editors and even on a fast computer, they took a long time to do something. I finally settled on Adobe Premiere Elements video editor and Elements for photo editing. Premiere seems to be fairly fast but hardware requirements are a bit steep. Seems the files we are working with for movies are so large that even transferring them from the card to the computer can take some time. I cut the transfer time by a factor of 4 by using a USB 3.0 port and a USB 3.0 card reader.
Like you, I really like MS Movie Maker and also the Office Picture Manager for quick edits of JPG photos. I installed both on my new Win10 computer. Their whereabouts are kind of hidden but they can be downloaded from Microsoft. Windows Live Essentials is still available for download and Movie Maker is inside the downloaded file. Run the installer and just choose Movie Maker. Office Picture Manager is inside the Office Share Point Designer 2010.