I'm using my original iPad charger, and a new cable I bought at the Apple store (just because I keep chargers around the house for convenient use). My original iPad charged about 20% an hour (I gave it to my brother), my new one charges about 16-18% an hour, only 11% an hour if I'm running an app like a clock overnight on my night stand, but it's still charging. The eight to ten hours of use I get during the day fully meets my needs, so plugging it in at the end of the day is good enough for me. If people's new iPads aren't charging at these rates, take it in and swap it.
My original iPad 3 had a smudge behind the glass, so I replaced it. I dropped my second iPad 3, so had to replace it with my AppleCare+ warranty. On all three new iPad 3s, their charging behavior has been the same, as I just noted above.
I empathize with people who want to play with or use graphics intensive apps with the power plugged in, and can't question their experience. But, if that's the case, it appears to me that the new iPad is performing as it was designed to, or at least consistently among the three I've extensively used, using the best technology available to Apple when it was being manufactured. If that's not good enough for these users, perhaps they need to consider some other device that will meet their expectations. Apple's not going to recall these iPads, and continuously swapping them out in the hope that one will meet their expectations doesn't appear to be in the cards. Time to move on, I'd say.
Perhaps next year's iPad with lower power components will come closer to their needs, or if they've soured on Apple's attempts to bring out the best technology as quickly as it can vice waiting for some utopian day when everything is ready to meet everyone's needs, there are certainly all those other "tablets" swamping the market eager for their dollars.