Currently all implementations suck if you don’t have one of the few supported HP printers†. Maybe a more encompassing solution would have helped the TouchPad (for example the ability to use any printer in the network) but I doubt that for such a feature alone TouchPads would have sold that much better.
Apple already had a feature implemented (in one of their betas) that allowed you to use printers connected to your Macs but they ditched it for some reason. Maybe technical reasons? Maybe politics? (Could they have a deal with HP?)
Having one (or even a few) HP printers that support the TouchPad – as you suggested – is demonstrably not good enough. The TouchPad flopped regardless.
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† Android is a different story but as far as I can see not a very pleasant one.