Clang plugins

Several months ago [1], I proposed a plugin API for clang, but I have seen no traction on getting it into the tree. Given the increased documentation for plugins (see <;\), I am beginning to feel that is urgent to settle on a direction for plugins.

In my opinion, the biggest problem I want to solve with plugins as they are now is the need for a cumbersome -Xclang -load -Xclang /path/to/ -Xclang -add-plugin -Xclang <plugin name> syntax and to replace it with a more tenable -fplugin=/path/to/ Beyond that, the other major issue is that the current way plugins are specified in the source code feels broken:
1. The PluginASTAction inherits from ASTFrontendAction, but it is never used as an ASTFrontendAction if -add-plugin is used. Given that clang is now a sufficiently robust compiler, I think the utility of having a plugin system that doesn't cause normal processing to occur is rather low (you could use -fsyntax-only if you really don't want to do anything other than parse the tree and run plugins).
2. The PluginASTAction does not lend itself to adding future hooks that do things other than passively watch the parser, such as modifying the list of optimization passes or tool invocations.
3. The use of the static registry initializer makes it impossible to gate decisions of what to make available.

What are people's opinions on this topic?

[1] See <;, <;, <;\.