IPW has a post about the chages to some characters in the Arcade Edition in SSF4. Information is below. Here is the link to the post on IPW if you would like to read it there. http://iplaywinner.com/news/2010/11/22/new-japanese-super-street-fighter-4-blog-post-translated-arc.html
-Rock Slash (when close, F+MP) has less recovery. Rock Slash > far st.LP > Roll now combos.
-Amazon River Run (DF+HP) has less active frames, has less frames of movement. The hittable box when Blanka is pulling back is now larger
-Surprise Back (B+KKK) has slightly more grounded frames at the start, making it easier to throw
-Rolling Attack (straight ball) has a bigger hittable box during rotation
-The distance of the Rolling Attack rebound is now dependent on the strength of the attack. LP=EX>MP>HP
-EX Backstep Roll (rainbow ball) has slightly less forward movement, making it harder to use as an escape. You can still do the same back-and-forth movement as before, however.
-EX Electricity's startup is significantly faster
-The second hit of cr.HP has a smaller attack box
-Tornado Throw does less damage
-Marseilles Roll's hit invincibility at the end of roll has been cut (the actual recovery is still the same).
-Soulless does 10% less damage
-Breathless does 10% less damage and has a slower startup. It no longer has Armor during his charge forward, and has more recovery on both whiff and cancel
-2 target combos added
-TC1 is cr.LK > cr.MK.
-TC2 far/close HP (first hit) > far/close st.MK
-The respective MK are cancellable, so you can combine them with Specials
-During the startup of far/close st.LP, the hittable box from the elbow to tip has been cut, making it harder to stuff.
-cr.MP has a faster startup. far/close st.LP (or cr.LP) > cr.MP now link. Since cr.MP is cancellable, cr.MP > Hands is now better, regardless of whether it hits or is blocked
-far/close st.HK has slightly longer reach
-UC2's hitbox has been extended downward, making it less likely to whiff
-UC2 has faster movement
-Is considered to be airborne immediately after the invinicibility frames of his backdash end
-cr.LK has more range
-st.LK is now kara-cancellable
-cr.HK attack box extended, and the damage box has been lowered slightly, making it easier to use as an anti-air
-cr.HP has slightly more active frames
-F+LP has a 3 frame startup (formerly 4 frames)
-EX Hayate is now armor-break, has a slightly faster startup
-Fukiage, when the arm is fully extended, the hittable box from her chest up is now barely there, while the attack box is extended, so there are now almost no cases where it trades or is stuffed. It still can't hit grounded opponents however. The start up for all versions have been revised (I'd assume to be faster)
-EX Tsurugi is now similar to EX Cannon Strike in what height the technique can be executed (instant EX Tsurugi?)
-UC1 damage distribution has been changed. It still does the same total damage, but because of the change, will do more when the scaling kicks in.
-UC2 has a faster startup
-The movement frames for forward and back dash have been reduced very slightly (making them faster). Because of this, now HP Hayate > FADC > cr.LK (and some other normals) > LP Hayate now combos. This vastly improves her mix-up game (throw or attack?)