Palladium's take on the Necromancer first appeared in RIFTS: Africa, and like everything else in that underwhelming product, this Occupation is a disappointment that does not fulfill player expectations and reveals that quality control at Palladium was (and remains) something that is akin to that of Taurus firearms: when good, great; when bad, horrible (and when good, often built upon another's framework). To play a Necromancer, as shown here, is to have one of those lemons and be in need of a juicer.
The player expectation for a Necromancer is not just that he be able to gather useful information through contacting the dead, but to call them forth from the grave and bind them through his will to be his slaves--his immortal, unyielding agents--and execute his orders. Furthermore, the player expectation includes the ability to manipulate the minds and flesh of living targets as well as all of the dead. In terms now relevant to talk of gaming design, a Necromancer is expected to be a primary-spellcaster that also has one or more pets to manage (some temporary, some permanent); in other words, they expect an undead-themed version of the Warlock class from World of Warcraft (which is, quite frankly, a very good iteration of a playable Necromancer) or the Avatar class from Green Ronin's (now out-of-print) The Avatar's Handbook. The former, to an extent, is met. The latter is lacking.
The Occupation has all of the expected look and feel, but lacks the substance. The Occupation's spell-list looks good on paper, but in practice the targets of the spells can either work around non-crippling effects or ignore them entirely. It lacks direct damage, and the pets that it creates are completely irrelevant to the expected quality of opposition in RIFTS; it doesn't matter if your NPC pets can reform after being blown to bits if you can't do any harm to them whatsoever because those you reliably control are too week, and those that are not cannot be reliably controlled- and that is the case with undead a Necromancer creates. Those who would want to play a Necromancer, therefore, must change how they employ the powers of this Occupation.
In short, a Necromancer is not a tactical threat. It is not primarily a strategic threat. It is primarily a threat on a logistical scale, and logistical threats are NPCs. When your man is someone who's ability to contribute at the table might as well be that of a Rogue Scholar or Scientist with some supernatural benefits and pets because properly leveraging what your powers can do and making the most of your Occupation's assets means that you're playing a different game from everyone else, you've got a problem. Working around this problem means changing your table to something that spends a hell of a lot more time and attention at the logistical and strategic levels, which means that you're playing a wargame or an economy simulation and not a true and proper adventure game (which is what a proper TRPG is). If that works for you, go for it; otherwise, your options are to cut it out from player access or to change the Occupation into something that works for you. Given how Palladium rolls, make some shit up that you think would be fun; you're unlikely to fuck it up any worse than it already is.