While I'd also support a ban on how-to-vote cards, at least voters can look at them and decide whether they want to follow what's on the sheet. But group ticket voting, with its susceptibility to behind-the-scenes deals, has to be cleaned up.
Preferences should come from voters, not parties. In particular, preferences should not come from parties playing a game that is essentially gambling. "They'll never get in, so we'll give them preferences in exchange for sending votes our way." How about giving preferences to the parties you like the most? "Well, if we don't win the seat, we'd prefer this competing party over that one."
It might be too late to save the Democrats, but at least we can see to it that extremist parties only get in when a decent proportion of voters want them.