I mean, is it a totally fine class to play with? It's not weaker than Alchemist or anything, so no. It's fine. You lose some incredibly irrelevant bomb stuff, who cares.
Is it a class that has great synergy with, and in fact the "best" class to use with Lich like he says? Hard no. Giving a very minor stat boost to summons (which are primarily useless meatshields) is not some huge bonus to lich. You have to win a battle first to use them and either you're raising useless crap to fight something harder or you beat something hard and don't need help for the rest of the easy fights in an area.
I get that there is a great thematic argument for reanimator lich but that's why mixing a power ranking with a feelings ranking is a dumb idea.