I honestly think that if you are serious about your coin and want to streamline your coin, you need to have a lightweight wallet ready to go with your launch. When I first got in to bitcoin, I skipped the client and went straight to Multibit because I didn't want to wait an eternity for my client to sync up. Also something tells me that your grandmother will not have the patience to wait for her wallet to sync up either.
Very much this. I'm surprised Litecoin/Peercoin/Namecoin/etc still haven't really got this sorted yet. If a new alt does come along that isn't pre-mined, has a sensible block reward scheme and mining difficulty AND has a lightweight client/wallet, it could take off hugely. Developers please take note.