Ic mains need to practice cg'Ing on different terrains now. Little bumps. Slants and other stuff can make you lose a grab if you don't know what to do
In my experience, slants and bumps don't make much of a difference for alt CGs. It does have a big impact on hobbling because your opponent will hit the ground earlier. As for the new neutral stages:
PS1: This stage doesn't effect us too much, and isn't really a bad stage for us. The opponent will some transformations to stay away. Some transformations give us ice block tricks. High ceiling needs to be accounted for when deciding what percentage to charge the U-smash during CGs. Also expect air camping from some MK players, taking advantage of some transformations
Castle Siege: Depends on the match-up really, Hylian explained each transformation well.
Delfino: The worst "neutral" imo for ICs. Nothing really helps us on this stage and some transformations really hurt us. Take advantage of the FD like transformation and whenever the stage is flying around. In the MK match-up expect MK to be under the stage often.
Halberd: Depending on the match-up, this stage isn't bad at all. The low ceiling allow ICs U-smash, U-air, and Up-b to kill earlier. The middle platform acts in the same way it does for YI. The slants also help our ice blocks traps. Unfortunately MK can attack us from under the stage on this one too, and you never want Snake to take you here since he will enjoy the low ceiling more then ICs and our ice block tricks are less effective when he has grenades.
And to briefly talk about counterpicks, whats worse about this stage list is that the opponent has Brinstar, Rainbow, and Norfair to choose from. Norfair is the worst imo for IC's and should be what are banned is used on (of course depending on the opponent, if your playing a snake main, halberd may be a better choice....but for MK, Wario, and even TLink.... just use your own intuition).
Brinstar take advantage of the kill zones, the can allow ICs to kill much earlier then usual. Also learn to use the lava to predict where your opponent is going to go and when your opponent is going to attempt to approach.
Rainbow just takes getting used too to play on. I personally prefer playing on brinstar because I just don't like the constantly moving stage. The boat doesn't hurt IC's, there are actually parts of it that help us. As the stage moves, take advantage of IC's u-air and b-air to put damage on the opponent as they are jumping ahead. Sometimes staying ahead of the stage and your opponent is the most advantage positions. Most grabs will happen on the boat or the last part of the stage. On the last part, take advantage of the low ceiling for early kills as well as the platforms to poke your u-airs through.
Pictochat: Basically a second FD with some tricks and a higher ceiling. Banned in my region so I can't talk about it much =/
Green Greens: Don't have any experience on this stage, can't remember the last time it was legal here.
PS2: Same as green greens, haven't played much on this stage. These tranformations hurt ICs much more then PS1 (well PS1 doesn't really hurt us). Wind and Electric transformation really limit ICs. The ice transformation will probably be the most useful for ICs, may get us easier grabs as the opponent is sliding. But I need to play on this stage more myself.
Frigate: Don't like this stage, I expect MKs and probably other aerial base characters to go here. But this stage isn't horrible for ICs, the second transformation allows ice block tricks like on halberd and the first one just makes our recovery more predictable/punishable on one side.
Of course, for any of the counterpicks that you aren't comfortable on, you can just use a secondary that performs well on them (like MK >.>) I don't see ICs winning much on any of the opponents counterpicks =(
