We have recently implemented Arc Media in Canvas. Because we have several LTI tools (e.g., YouTube, Office 365, etc.) installed at the account level with placements in the Rich Content Editor, the Arc icon in the RCE is at the bottom of the "More External Tools" sub-menu.
This has made the availability of this new (and fantastic!) tool less than obvious for our users (both faculty and students). (I suppose if Arc is one of the first LTI tools you install, this is a non-issue, but for those institutions who start with Canvas and later implement Arc, this is an issue.)
I have asked the Arc implementation team about re-ordering the sequence of the LTI tools (at least the ones with placements in the RCE) to promote Arc to the top of the list so that it appears alongside the native tools in the RCE. So far, no one has been able to help me with this.
My suggestion is to promote the Arc LTI placement in the RCE to a place alongside the native tools, rather than having it default to the bottom of the "More External Tools" sub-menu.
Another option would be to add a feature to allow admins to edit the placement/order of LTI tools in the RCE at the account level. The current sequence seems to be "first-come, first-serve" without any option to reorder them.