New Vanaduke fixes/buffs
1. As listed in the patch notes, the corner pillars have been replaced with water fountains. The old water fountains have been removed. You can no longer trap Vanaduke against objects.
2. You can no longer reliable trap zombies against walls to make them inactive. You can still avoid slag guard spawns if you do not kill all the zombies, but since the zombies will be walking around instead of against a wall, you need to be careful not to shoot them.
3. The lava tile limit appears to have been increased in phase 3 to phase 5 levels. You'll have more lava to deal with sooner. There is still a cap to the amount of lava allowed, so it's not a big change.
4. The shivermist range change is just large enough to make it difficult to spam freeze on him in P5
Judging from the skill level I generally see in PUGs and even my own guild, I'm guessing most players will no longer be able to reliably kill him.

Nothing about this fight was changed except for the pillars and water fountains. Nothing regarding his attacks were changed.
I tried trapping the zombies for a good 2 minutes and failed to do so. Before the patch I was able to do it in under 30 seconds. Maybe I'm just having an off-day or something, but it certainly seemed different.
I got a lot more lava on phase 3 than I ever got before.
While his attacks may not have changed, the tools that we have to fight him have. Whether intended or not, these resulted in buffs to his difficulty.
Yesterday on my Vana run I couldn't believe the amount of lava accumulating, I had never seen so much. Obviously, this was before the update. It was a party of 4, we had him trapped on the bottom left so he was pounding away with his mace. I spent about 80% of the time picking up water to throw at the lava, utilizing both of the waters at the bottom. Normally I would throw water every 4 clips or so during Phase 3.
Probably just the RNG screwing with me.
I certainly don't have have a problem with not being able to trap him behind objects. And pushing zombies and abusing shivermist always did feel a little like cheating since it seemed like neither were intended strategies.
But at this point, I think they should just remove the zombies and slag guards. Or change their behavior. Anytime I see designers throw basic enemies into a boss fight, I always imagine them saying "This fight isn't difficult enough. What easy/lazy change can we do to make things more difficult?". The smaller jellies and scuttlebots in Jelly King and Roarmulus Twins respectively seem to fulfill that same purpose.

i blame those foolish players that post videos of the trapping vanaduke techniques for the whole wold to see
Fight will probably be about the same.
I'm more concerned about the 55 Almirean Seals that I ""lost"" when the prices got cheaper :P
Refund me a fov Nick >:

i blame those foolish players that post videos of the trapping vanaduke techniques for the whole wold to see
Don't vilify them though ;)
Exploits are exploits. When they are balanced/fixed to be what they were intended to be, the best thing to do is just simmer in the fact that you were able to enjoy it while it lasted.
In my case: Hearthstone pendants. Obviously a 1* item by price and stats, but for some reason was a 2* item, and thus sold for more CR to NPC's than it should have.
You can no longer reliable trap zombies against walls to make them inactive.
You still can. It's not very hard. As for everything else, yeah. It's not so easy anymore.