I hate the way they do that.
Yes, keep a traditional-style, easily recognisable kit for your main one. Absolutely.
But for an alternate jersey to be a completely different design AND colour set? Nup. Any casual observers of their games wouldn't know what the away team was. They even, on some teams alternate jerseys, even change the colours of the logo.
Personally, clubs should keep their colours on all jerseys (barring special occasions), but should be free to play around with whatever crazy designs they like on the alternate jerseys, so long as they do actually provide a point of contrast to the main.