I have to say I'm not really a fan of modular type cages - largely because I have mostly Syrians and most modular cages are too small for them (I mean the modules aren't big enough no matter how many you attach, if you see what I mean).
However, for a lone winter white a lot of them would be ok - you need to remember they don't always climb well so vertical tubes aren't a good idea - and remember the cleaning out will get a bit tedious
I'm not familliar with the Habitrail Playground so I looked it up:
http://www.animalinstinct.co.uk/acatalo ... nd_27.html
Is this what you mean? I'm not sure how big that main module is but, depending on size, it looks ok for a dwarf - I'd set it up all on one level though as I don't think our ww's would climb those tubes. It looks to have better ventillation than a lot of modular cages - another thing to check would be the space between the bars - winter whites can squeeze through pretty small spaces.