I've used NetBeans, jEdit, IntelliJ, Firefox, among other plugin-extensible tools. One problem these all have--including IntelliJ--is that apart from those officially supported, plugins are generally not tested, reviewed or recommended by the makers of the tool itself. In the worst case (true for all those tools) the plugin repository includes quite a few "junk" or incubator-quality plugins that don't deserve to be used in a serious development tool. What I periodically find is that plugins that aren't actively maintained throw exceptions, for example, and when this becomes enough of an annoyance I pull the plug and remove the plugin. The current system of tracking plugin quality via voting, and commenting via a discussion page (and unmaintained wiki) doesn't take us far enough.
I would love to see some sort of review system by IntelliJ for plugins. I see and appreciate the voting system, appreciate that JetBrains has lots of work on its hands, etc.--but I feel the current system includes too many unstable plugins and something in the process could be improved.
Here are some practical ideas:
1) if the plugin is open-source, plugin developers should be required to distribute it with (an) IntelliJ project file(s) so that one can easily retrieve, debug and improve the plugin.
1a) would be nice to have a dialog or feature to pull plugin source down with the plugin (jEdit supports this), optionally pulling in the plugin project or plugin module(s)
1b) some way to encourage collaboration would be useful. for example, if plugin developers were hosted on site X (sourceforge, google code, codehaus, java.net), it would nice neat if IntelliJ could take care of the grunt work of getting CVS/SVN set up so that source code could be downloaded, and patches could be submitted more easily
2) the JetBrains team could help by marking older plugins which have been superseded by features in newer releases of IntelliJ. currently there is no filtering on the plugin list, which includes very old plugins that are no longer useful past a certain version.
3) the plugin dialog could be extended
3a) to include links to the source (and maybe a checkbox to download it)
3b) to show the number of votes on a plugin
4) a quick tool to vote on plugins would be useful--for example, when disabling or removing a plugin, an option to vote and comment (to be posted to the plugins website)
5) some way to capture activity in plugin development would be helpful--e.g. plugins released just once would have a lower rating than those regularly updated
6) include vote categories for "stability", "configurability"
7) when a plugin throws an exception (or is suspected as the cause), it would be great to be able to
7a) disable the plugin immediately
7b) vote on it
7c) file an issue or
7d) submit a comment to the plugins site
7e) track the number of exceptions thrown per plugin, across users (optional, of course, as this info would be uploaded)
8) i get a very bad feeling from plugins distributed as binaries, with no email address, plugin home page, or developer home page provided.
9) nice to have--assuming the source was available, a PMD or Checkstyle configuration could verify (and warn) if the plugin performs IO, network operations, etc. (esp. for plugins with no email address or home page).
Sorry, that's a long list! But you have such a great start in the current plugin set that it's worth asking for it to be first-class.
If you think any of these are worthwhile, and might be implemented in the future, I'm glad to add any or all suggestions as feature requests in JIRA.