I don't agree. We aren't talking about the wisdom of subpages, we are talking about the typing shortcut and the linkbacks. Both are not very useful.
We have hundreds of archive links and user subpages, often on pages with long names. The benefit of shortcuts and linkbacks is far from negligible as we approach a million pages.
But we really should discourage them generally by not "supporting" them with useless cute features.
The reality is that people are creating them, including yourself: http://www.wikipedia.org/wiki/User:Jimbo_Wales/Why_I_oppose_a_cabal http://www.wikipedia.org/wiki/User:Jimbo_Wales/Statement_of_principles
Either you ban subpages entirely, or you support them properly depending on context. But choosing not to support them to "discourage" their use is schizophrenic.
Regardless, I primarily added the support for my own use. If you intend to block this feature on Wikipedia by imperial decree, I don't care much.
Regards,
Erik