You need development tools for designers

True. Same goes for Canvas.

few companies have the manpower/skill to create a dynamic (animation-friendly) design/development environment targeted at web *designers*

This is true - there are some IDEs but they are mostly targeted to SVG in the mobile space. This is looking like it's starting to change though.

Canvas is a much simpler and smaller standard

True. Another way of saying this is "SVG is more powerful" ;). See: DOM integration, event handling, linking, styling, fonts, filters. As with everything you have to pick the right technology for what you need.

Browsers that integrate Canvas usually implement it in its entirety"

Nope, see Canvas text API or talk to the Bespin guys.

It really depends where they are in the release cycle. Currently Minefield is stable enough because they are at Firefox 3.1 Beta 2. Months ago, that was not the case. Once Firefox 3.1 is released, that will also not be the case...

Metaphorically's point still stands: Minefield is not a new browser, it simply a nightly build of the Firefox 3.1 codebase and as such, hasn't had the stability testing that the betas and release candidates and even the alphas get.