Mojang has now got a reporting infrastructure for players to report bugs in the PC version of Minecraft (Introducing the Minecraft Bug Tracker!
). Like the bug reporter for the Pocket edition and suggestions for the Minecraft API, it uses the JIRA system. In fact, Mojang and JIRA are now helping each other make JIRA better.
MC bug tracker: http://minecraft.net/bugs/pc
MC Pocket bug reporter: https://mojang.atlassian.net/secure/Dashboard.jspa
(see also Where to report Minecraft Pocket Edition bugs
MC API proposal: https://mojang.atlassian.net/browse/MCAPI
(see also Where to place Minecraft API requests