So will this make a web developers life easier? Well, it depends on what Microsoft actually come up with as regards to Spartan, but it's hard to believe that it would be more difficult to work than Internet Explorer. But the sad thing is, it probably wont make life easier anytime soon. Tech savvy people tend to go for browsers like Google's Chrome. When it says it needs to be updated, they press the yes button. Explorer tends to be used by people with less tech knowledge and is quite often never updated.
There are millions of people in the world surfing the web with old outdated versions of Explorer and there will be people using the more recent versions for years to come. This means that a website developer will still have to take Explorer into account when developing websites for sometime - but at least there is light at the end of the tunnel