So I was mega-practicing wall combos over the weekend. Man, Yoshi's got great stuff there...others will probably have posted some of these, but let me sum up what I was practicing:
9K W!, 3B W! 2A+BB, 3B, a:B+K, DNK, 2K = 100 dmg. From another juggle starter that wall splats it's more damage, up to I think 116 for starting with 6K. Just requires that you get that second W!, which works best if the opponent is either directly between you and the wall or if the wall is closer to your left side (9K and 6K both launch to the left, but 9K only slightly so).
The second wall-splat means your 2A+BB will put the opponent into stun state, guaranteeing relaunch with 3B (but no third W!, obviously). Because you're close to the wall when this happens, DNK after 3B, a:B+K hits, meaning you don't have to guess if they're going to tech out of 66A+B or not (more damage vs. guaranteed finisher and oki setups).
If the second wall splat is at a certain timing (I think if it's a very high wall-splat), the 2A+BB gets them but doesn't return them to standing, even though the 3B relaunch will still work if they do anything but lay there (I was testing this with counter off, techs random and the combo meter didn't reset and was never rolled), so you will at least almost always get to that third launch if you see the second wall splat. If the angle's slightly off to one side, the opponent will start to go parallel to the wall, but usually not far enough away to prevent the DNK, 2K ending. If it goes that far, though, 66A+B or Deathcopter.
What you can also do, if you have meter, is after the second W!, 2A+B for the stun, 66aA+B+K, bA. Massive damage, if you can spend some meter and get the timing right. Seems to be slightly spacing reliant as well, since you need to have the opponent stay between you and the wall or bA won't connect. Didn't try on every character (was beating up Pat for some stress-relief), so probably still character-specific.
If you don't get the second wall splat (because you were too far to the right or for whichever reason), you have any of your options post 3B LNC still, including CE.
Bottom line, I guess, is if you see yourself headed to the wall, try to stay on your opponent's right side so the wall is at least slightly closer to your left. As soon as you see the opening, launch. If you get the one W!, 3B. If you get the second W!, laugh heartily as you proceed to do guaranteed damage that's more than most characters' unscaled CE damage. []