The rule to move the attacker to the target tile was one of the main changes in my latest version of civ2civ3 rules, and you are right that I should have explained the reasons. I have tried to explain it in this post: viewtopic.php?f=14&t=614&p=3872#p3872
You use in GT a modified version of the ruleset, and I know that little changes to the server settings could affect a lot the resultant strategies, specially rules related to unit movement, so I'm not sure how this rule will work in GT, but I find it important to enable it if infrastructure is restricted and you find it too hard to reach enemy cities.
I agree kill stack is one of the most important rules to keep the balance of the combat in freeciv. I never liked that civ3 removed it.