Re: PvM 1.13 ExplosionMancer guide
It gives me great joy to see people still finding this guide after all this time!
About enigma and teleporting with the merc. You would have to sacrifice the FCR in vipermagi and compensate that with something else. Try as you might, it's hard to get everything (offensive and defensive capabilities) in the same packet with enigma. It is, of course, a matter of preference. I prefer to be invincible and it is hard to do with other gear choices (getting max resists, max block, huge bone armor, double prayer and the rest in the same package).
About max block. I would definitely recommend it, because it's great against archer packs. Of course you can, and should, cast dim vision / attract to these packs, but max block is for the situation when you haven't cast the curse yet. It sounds dumb here, on the paper, but it happened to me lots of times when playing - an archer pack shoots you from the edge of the screen and you respond by casting a curse on them. Of course bone armor absorbs a lot, but max block definitely helps and is great against frenzytaurs and the likes! But, again, it is a matter of preference! I just absolutely love homonculus as a shield, with all the blocking and resists, and the fact is it is quite cheap - you can trade it with pgems or the hellforge drops if you go untwinked. It is the item that gives your character most safety, I'd say.
About insight. I actually have a cheap gear section in the guide where there is a lot items that help you with the mana situation. You can do it without insight, but you sacrifice some efficiency without it. What can I say, Insight is such a great merc weapon for casters. And it's quite cheap to make, if you make it to just regular polearms and leave the superior ethereal stuff alone until you have more wealth.
About CTA. Yes, you can play this build very, very safe without CTA. It is just icing on the cake to have that much more life as a buffer. If you follow the guide as I wrote it, you see that I focused really hard in NOT taking any damage instead of building up a massive hitpoints pool.
Lastly, about the guide. There is a lot discussion about gear and skill decisions here. It is not a bad thing to ask for opinions, but, I fear, some here may think that there is an absolute answer to every problem. But, in fact, it all comes down to preference in a lot of things. For example, it is very hard to answer in somebody else's stead if (s)he would like max block or not. I think it is a personal decision and one that the person probably needs to figure out by himself. I don't want to, in any way, discourage discussion here, but I just want to point out that part of the fun that Diablo II gives is finding what works for you personally by experimenting with different gear, skill selection and play styles.
I never thought about this guide as a definite way of playing necromancer. I just experimented and found it fun - so I decided to share my findings. I'm very flattered about the trust people put in my opinions, but the fact is the guide is just an idea, just a starting point. Each one need to make the journey by themselves. Some might stay closer to the original plans than others. You are all welcomed to share your journeys here, so to speak