1. Guile and Glenn added to the main cast.
In Chrono Cross, these two characters were optional. In the re-release, I would make them mandatory. Explain this logic to me: Glenn is one of the best characters in the game, but can only be unlocked if you opted not to save Kid with the Hydra Humour. Of course, most of us went and got it anyway because Kid was awesome, and we got Korcha instead. That's quite a price to pay for NOT being a cold, heartless bastard.
As for Guile, if he really is supposed to be an amnesiac Magus, he too should be mandatory. Guile joins you in Termina to raid Viper Manor (I would rewrite the circumstances surrounding this, as well), and at some point in the game he recovers his memory and becomes Magus once more.
2. Double/Triple-techs for everyone in the main cast.
From what I remember, the mandatory party members were Serge, Kid, and the Acacia Dragoons. There may be more. In any case, with Guile and Glenn added to the list, that would make quite a crew right there. I don't expect Square to remove all the optional characters, however I do expect them to add more depth to their crucial ones. Every pair must have three double techs apiece, as well as a triple tech with Serge. I would give the Dragoons their own triple tech as well.
3. Serge unmuted.
Why do game developers not give their main character a voice? In most cases, it's because the main character is intended to be the player, who fills in the blanks on his own. This was the case with Crono, who didn't have a past of his own and so he is intended to be the one holding the controller. Fine. But Serge? Serge's past is by far the most intriguing aspect of the game, and he has gone through so much turmoil that it is simply impossible for us to imagine ourselves in his shoes. He spoke in Radical Dreamers, and he should have spoken in Chrono Cross -- in my opinion, at least.
4. Ditch that collecting items shit (weapons/armor).
One of the most annoying things about the game was that I not only had to buy elements, but that I couldn't buy weapons and armor unless I had the necessary items. This was obviously inspired by the trip to the Prehistoric Age in Chrono Trigger, when money didn't exist and to get new weapons and armor you had to collect whatever was dropped by enemies. To me, this is fine as an option, where you can get somewhat stronger weapons and armor if you take time away from the main quest to go through the process of finding the items. However, in a game that doesn't even allow you to level up, I would at least like to be able to update my equipment without dealing with the bullshit. Oh, and while we're on the subject...
5. Let me level up my characters.
Fighting bosses will level up your elements or something, I don't really remember. But, that was fine. Experience points should be brought back for leveling up characters' stats, however. This is a straight-forward request.
6. Chrono Trigger DS extras.
Basically, the same extras that were in CTDS, but for CC. Again, pretty straight-forward request.
That's all for now.