I actually like Diana/Tom (yes, he was an annoying jerk at first, but those were the same issues where Diana couldn't pump gas and didn't know what a credit card is; can't we just ignore that idiotic characterization and judge the characters for the way they are acting now? Since Gail started writing WW, I quite like Tom and his interactions with Wondy), but I have to admit, I too would have preferreded it if they had said "for Donna Troy to have a sister."
Family before boyfriends, please. Bruce gets his "father", and Lois is good for Clark because they have been married for years, but a guy who has known Diana for just a few months shouldn't take precedence over her sibling.