It's generally considered that the game becomes easier after killing the Master, so you shouldn't have much problems after that. A few caveats, however. I'm almost done with my necromancer playthrough and I've died only twice (once to get lich form and once in a vault). The "legit" death was in a vault in the East, which is one of the caveats. Optional content in the East is hellish, vaults become gauntlets you almost can't escape from, the infamous Vor armory room exists, sludge tunnels are a whole mess if you go for the achievement(s), the optional areas like the underwater temple and moon lake aren't exactly easy, etc. So I suggest just beelining the main plot if you want to complete the game, with the exception of the backup guardians when you go back to the West. They are easy and fast, but drop good items. Since you'll be max level pretty soon after going to the East, there isn't all that much of an incentive to complete optional areas unless you want the unlocks. The items you get are a bit pointless imo because you are already quite powerful. Yeah, you can get some pretty crazy good items and I'm not saying it's not fun playing around with them, just that if you want to kill the last boss it's safer to avoid the optional content. Even though Necromancer is grotesquely overpowered, I still won't go do the optional content in this playthrough because the weaknesses of the class (lack of mobility, lack of survivability cooldowns, loss of 90% of your power when your minions die if you are minion-based, tight corridors) don't give me hope, let me tell you. I think you can go do the unlocks after you complete the game anyway, though? But yeah, the East has the tendency to make you overestimate your character and boldly go into every danger imaginable, so don't fall into that trap ;d
Oh, and the orc prides are boring compared to the entire rest of the game. They are too long and samey, with basically nothing in them that can considerably threaten you. If I were to mod the game, I'd remove 2 of them. The believablilty of the story also suffers because of them. The paladin chick in the gates of mourning tells you they've fought the prides for years, if not more, but you stroll in there and massacre the entire orc population on your own. Everything before that is pretty par for the course for an RPG adventurer, necromancers in old towers, rabid animals in a forest, clearing out caves, etc.