Yes, you need iTunes to search for (and purchase) any content available via the iTunes store. This is the way it's been since the start, and it hasn't slowed down iTunes sales, including iPhone app sales.
The iPod, iPhone and iPad platforms are all very thoroughly controlled by Apple, including gatekeeping functions. If that bugs you, then yes the iPad is not for you, and you should find a competing product that better suits your preferences and/or needs.
But regardless of whether or not you personally view this as "opaque" or bad form, it won't result in them losing sales.
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