The notes say that the base damage is being increased from 10 to 40 at level one. So this will probably offset the total AD damage so that it is relatively the same damage wise at level 1, but with it scaling into the game now, eating a trap later will hurt more.
Most people around level 9 will either just have their component items or a full IE, so that's roughly 40 (BF Sword) to 70 Bonus AD. Get to late game Caitlyn with a standard build of IE, Shiv, RFC, BT, Boots, LW upgrade.
With a BF sword and Dorans, that's 125 total, 57 bonus.
With IE and Dorans, that's 155 total, 87 bonus.
With full build, that's 299 total, 209 bonus
So right now:
BF Dorans: 190 + (0.6 x 125) = 265
IE Dorans: 190 + (0.6 x 155) = 283
Full: 190 + (0.6 x 299) = 369
PBE
BF Dorans: 240 + 57 = 297
IE Dorans: 240 + 87 = 327
Full: 240 + 209 = 449
This is all without resistances in mind cause I don't want to deal with that, so we're just comparing numbers. My test in Practice Tool had these numbers for her current kit vs Target Dummies.
BF Dorans: 97 Regular head shot, 234 Trap Headshot, 351 Trap Headshot Crit
IE Dorans: 140 Regular head shot, 287 Trap Headshot, 488 Trap Headshot Crit
Full Build: 326 Regular head shot, 555 Trap Headshot, 974 Trap Headshot Crit (Tested with IE, BT, LDR; No RFC, Shiv, or boots)
So, right now she's hitting people with 100 armor with maxed traps for those numbers. And you can see that with the new changes, that should increase. Not insanely, but it will increase it.