There is a dilemma that plugin authors face from time to time: seek fame and fortune by developing their ideas as a plugin, or set aside personal concerns and serve the community by working to introduce the functionality into WordPress itself.
If you have an idea for a plugin that adds serious functionality to WordPress then you have a decision to make. On the one hand you can develop a plugin, promote it, and reap the 15 minutes that it brings, and on the other you can present a patch to the WordPress trac, push the benefits, and hope someone takes it up. So how do you choose?
In some cases it really is obvious.
Controlling the advertising that appears in different positions, allowing comments to be sorted, adding a tabbed interface; these are all things that have a limited apeal. Limited when compared to the entire WordPress user base anyway. It should be clear that these things don’t need to be in the core.
The uninstall functionality that was recently discussed over several posts on this blog, and over at Weblog Tools Collection, was clearly something that should be in the core and would be hindered by being a plugin.
In other cases it is not so clear. It still surprises me that WordPress doesn’t feature a form builder of its own. I have built my own, although I have not released it, and there are several form builders available for download from the WordPress plugins repository. Is there a blog that doesn’t need a comment form?
Aside from the issue of whether it belongs in the WordPress core there is also that matter of ease of development. Plugins are not difficult to write; however, you will always be restricted by the places you can hook into. It is easier to develop changes to the core because you are creating your own section of pipeline instead of using the closest input and output valves to try and intercept the flow.
Even if you do decide to write it as a plugin, consider the case of tagging. How would you feel if you spent a year or more developing and promoting a plugin only for that functionality to be added the core, in the process making your plugin obsolete?
If it is something that may belong in the core then it really comes down to your choice: do you want to use the plugin to further your own success, or are you happy to take anonymity for the good of everyone? That sounds like a loaded question, and you can choose to take it that way if you want, but when you are developing something to give away you have to take the rewards you can get them; it isn’t my intention to make a moral point.