not only recast the famous characters from The Original Series
, but it essentially recast the look of Trek's 23rd century as well. The uniforms, the ships, the control consoles, phasers and other props, even the San Fransisco skyline, have been changed.
This isn't the first time Star Trek has done this - The Motion Picture
handwaved an Enterprise refit while changing everything, and Star Trek: Enterprise
was set a century prior to TOS. STXI's handwave is "alternate reality branching off in 2233", and although that covers changes in the story and some details, it's no more an excuse for the scope of visual changes than TMP's refit (an Enterprise refit of course explains the difference in Klingons between TOS and TMP!
In my opinion, if a Gorn is "really" a fearsome and intelligent lizard monster when it's blatantly a man in a bad rubber suit, and if Chris Pine and William Shatner can both be James T. Kirk, then the USS Enterprise NCC-1701 is an advanced futuristic starship, whether it looks to us as it did in 1966 or 1979 or 2009. The exactitudes of it's design are irrelevent.
In other words, Trek's visual/technical continuity is mallable, and can be changed as easily as an actor is replaced. "It looks different/too advanced/It's all wrong" and similar arguments are as meaningless as complaints about the colour of Saavik's or Kirk's eyes. As long as the basics remain the same, the details doesn't matter.