I voted no - I can live with a change to the SMAC system (and may even favor it), but I certainly don't want to go back to the Civ3 artillery. Since the poll doesn't state *which* change is intended, I vote no to stay on the safe side. I wouldn't want my vote to be counted as supporting a Civ3 system, for example.
That's not a good poll imho. You may end up with a majority of people wanting significant changes, but being totally discordant about which changes to make. You may even get a majority for change when the fans of the current implementation are the largest single group. (Example: 40% favor the current system, 30% favor the Civ3 system, 30% favor a SMAC system. The poll will yield a majority for change, although the largest group favors the current system. You would also get a majority for change if any of the two other variants were implemented and you asked this question.)