The folks at Firefox periodically look for new ideas from its band of developers. In its latest brainstorming session it appears that Firefox is looking to simplify their browsers. Recent hic-ups with their browsers on Windows Vista and Windows 7 have made the developers take a hard look at their work, especially the interface.
Taking a few cues from other browsers that have entered the market the team are focusing on maximizing screen real estate and eliminating redundant buttons from their browser. For an example the menu bar and the buttons take up a lot of space, sometime much space. Aside from maximizing real estate the team is looking at usability. Most current users subscribe to a many services such as Gmail, Twitter, Digg, del.icio.us etc. Thus the team feels that grouping all of these most used services together and pinning them to a portion of the screen where they can be easily accessed will be useful. This is by far the biggest change that users will see in the new Mozilla Firefox 4.0 apart from the increased screen real estate reduction in redundant buttons. The Mozilla team are also planning a few more subtle changes like limiting the page title only to the tab as opposed to the tab and the title bar of the browser, as it is currently done. This may not improve performance or help you out, but it is part of a cleanup process that the organization has undertaken.
That being said, no one can really comment on how the new browser will be received by the masses. In early days Firefox was hailed for its security and then its versatility by using plug-ins. We will simply have to wait and see if it still is a better browser than the new Internet Explorer and whether it will be able to gain market share and beat out competing browsers.