Yeah, most of the new FG's are hard to impossible for Sudden Killer.
Serket - medium. Early Dim Shield chain and it's over. If it comes too late, you'll be too poisoned. However, if you want a better chance against Poison FG's, use Purify instead of Sundial.
Jezebel - very hard. You -can- trick her into stealing some pillars, but her PC density is huge: 8 Steals in 70 cards. Luckily her offense is often quite low, so you may survive one or two turns without a Shield later on. If she gets an Air Nymph though, you should probably pray you can bolt it, which reduces your chances either way.
Akebono - skip. Not only does he play Unstoppable on Overdriven Massive Dragons, he also has 4 Chimeras for a finisher. You might think having a Lobo helps your odds, but even with SoG's the total Unstoppable damage is far, far too high.
Hecate - hard. Rage Potion damage can't be avoided, nor can the Poison from LS. Try to bait Steals with pillars (i.e. wait a turn or two), or she'll burst damage for the kill after stealing your Dim Shield.