I like some aspects of the new design, but somehow it is over-designed and looks like something intended to be a 'magic wand' rather than the last one which seemed like it could have actually been a simple tool that the doctor 'souped up' over time. The fact that the TARDIS seems to have built the new one, and has it there waiting for him solidifies it as more an extension of the TARDIS than just a handy gadget.
It isn't necessarily a bad thing for them to make this change, but I could do with a little less of it now and again when it seems to be able to do anything and everything. I'd have rather seen 11 build a new one himself as part of the plot of an episode, rather than just have this shiny new lightsaber-looking thing waiting for him in the new console.