Love having my skeletons with me. Only level 10 right now.
What I am doing is alternating points in raise skeleton and skeleton mastery. Seems to work pretty well. I also put two into amplify damage as I have an item that gives + skill level to that. Having fun with it.
One is enough in AmpDmg, I would use +skill items for that.
When I go with a skelemancer, I alternet between raise skeleton and skeleton mastery till 5-5, than I max raise skeleton, while activating Clay golem ,golem mastery and summon resist and decrepify on the curses tab.
Than max skeleton mastery. From there you can go Corpse explosion or max skeleton mages. Both way is fun!
Skelemages are enjoying to “disappear” frequently and are easier to blown away on hell than skeletons.
Clay golem + decrepify will keep the act bosses in slowmo while your skeles can gut them 