The new lineup means that businesses looking to deploy iPads have a greater range of choice. Each model is naturally a better fit for different kinds of tasks. The iPad mini is preferred by many doctors simply because it fits in a lab coat pocket. A field auditor for a company would prefer the larger display and larger keyboard options. A sales or marketing professional would be an ideal choice for the iPad Air because of its size, weight, and value as a status symbol when meeting with customers or clients.
At the same time, that choice isn't coming with fragmentation. All of the iPads in Apple's new lineup can run iOS 7 complete with all its security and enterprise functionality (though certain features like Siri aren't available on the iPad 2). Developers only need to design for two screen dimensions when they create iPad apps: the 2048 x 1536 resolution used in the iPad Air and new iPad mini with Retina display (and the third and fourth generation models) and the 1024 x 768 resolution of the iPad 2 and original iPad mini. These aren't small advantages when you're looking at a large deployment and they shouldn't be overlooked.
It's also important to acknowledge that Apple's pricing strategy with the the iPad 2 and original iPad mini applies differently to bulk purchasing by a company or school than it does to individuals. If you're just buying a single iPad for yourself or perhaps a couple as a Christmas gifts for your kids, that extra $100 isn't too extravagant and is easy to justify. If you're a ordering a hundred iPads for use as POS systems in a retail store or a thousand for all the kids in your school district, that savings is much more significant.