+tree items and synergies

[Wyrm]

as are the druid summoning synergies (these synergies already existed in 1.09 and they weren't nerfed into fitting the new synergy model).

I don't really think of those as synergies, they're just skills like the Necro's Summon boosters (skel/golem mastery, summon res) that have a multi-use.

Edit: yeah, yeah, I know that's what the synergies are, but since they existed pre-1.10, it's hard to think of them as actual synergies.

If I'm not mistaken, Valk also gains the +skill bonuses for Dodge, Avoid and Evade.

What do the boots do? And buggily?

If you don't have any other sources of Bone Prison (ie no points or items with +prison) then it will treat the level 33 Bone Prison on the Marrows as a synergy (hence bug), giving a rather huge bonus to your other bone skills. There are several other items that will do this, namely anything that has charges (and items that have +skill without the specific class mentioned like on scepters, etc.). Given that Blizzard has made no announcements whatsoever that they're even thinking about updating D2 again, chances are they might just wind up calling it a feature and saying it was intentional.