Wii: Retailer leaks peg both S&P2 and MH3 for April. I think Japan will see Galaxy 2 for Golden Week (though the west might not until summer). ARF is confirmed for June. Japan should get Basara 3 by June.
DS: I think America may get DSi XL and 3D Picross in Q2 instead. We may get DQVI by June too (to give DQIX enough time later in the year). Not sure what else is up, Ghost Trick and Ninokuni in Japan and Inazuma Eleven should (finally) hit the west in May.
Everything else notable (that we know of) will likely come later imo.