FIrst, this is a beautiful website- idea, design, execution. I use it for aviation weather planning. You guys are talented. I'm a longtime web/mobile developer, but can't touch this.
Agree with your keeping the basic UI simple; there is a lot of stuff getting added, cool stuff (like comparing the models, this is just awesome), but please make sure it doesn't get bogged.
Regarding a 3d mode: would be best as option or even separate. Have you considered using cesiumjs for your globe? They have done a lot of the hard work already, and some of the capabilities might open up new opportunities (e.g. doarama).