As far as i'm aware, to become relevant, PMs demand an unreasonable level sink for a mediocre reward, and don't really get to benifit from any of it's supposed strong points, I.E Summoning and Grafts, either because of being outclassed or because the mechanics behind said features are subpar.
Even after recieving a buff (which should be mentioned- because it means the state of the class is at least acknowledged), and later given the option to further strengthen their undead with another unreasonable feat-sink with the new undead feats, the class remains subpar because these boons do not really remedy the problems the class faces (A subpar caster that can become a wonderful tank [Although DDs and possibly Druids do it better] after an unreasonably long time sink with little to show for it).
PMs should, in my opinion, see these changes;
Summoning: Summon undead and Summon greater undead should take your total caster level into account, and not just your PM level. Furthermore, PMs should either recieve some of the new undead feats as part of their progression, or simply recieve a big flat boon to any of the summons they conjure.
This could also be remedied by simply altering the class' summoning tree and replacing it with existing undead monsters (I.E Huecuva), as NWN's base undead are amazingly bad (even after calculating the new undead feats).
Grafts: Are a cool feature, but are ultimately quite useless when you look at their DC and function (the minimal level of acquiring Paralyzing touch is 9, when it's DC of 10+[pale master leve]+CHA is below mediocre).
Therefor, allowing PMs to empower their Graft related features via feats / modifiers, and giving them more uses (I.E healing their summons) would help the class a lot.
And, since the last HAK updated contained homebrew feats, consider these optional feats selectable / part of the PM's progression tree:
Danse Macabre
Type of Feat: General
Prerequisite: Greater spell focus: Necromancy, 2 Pale master
Specifics: The Pale Master is able to animate more undead, and will always animate/summon/create an additional servant from a spell or ability [bar familiar].
Command obedience
Type of Feat: General
Prerequisite: Spell focus: Necromancy, 1 Pale Master
Specifics: Once per a day, the Pale Master is able to force an undead to roll a Will save or automatically become dominated as per the Control Undead spell.
DC: 10+Primary casting modifier + Caster level
Tailored Perfection
Type of Feat: General
Prerequisite: Greater spell focus: Necromancy, Pale master 10
Specifics: After extensively modifying his body, the Pale master’s physique reaches its prime.
Specifics; The character gains 10% movement speed, tires less quickly [added exhaustion threshold], and becomes completely immune to poison and disease.
Undead mastery
Type of Feat: General
Prerequisite: Greater spell focus: Necromancy, Pale master 5
Specifics: The pale master may assert his control over summoned undead for a longer duration.
Negative energy bolt
Type of Feat: General
Prerequisite: Pale master 2, Spell focus: Necromancy
Specifics: Two times per day a pale master may unleash a bolt of negative energy. If the ranged touch attack hits, it deals 1d6 (per caster level) points of negative energy to the target.
Grave feast
Type of Feat: General
Prerequisite: Pale master, Spell focus: Necromancy
Specifics: Any undead creature summoned by the pale master receives +3 vampiric regen.
Artisan of bone
Type of Feat: General
Prerequisite: Pale master, Spell focus: Necromancy
Specifics: The pale master has learned how to further empower his graft, adding X DC/Uses to any related graft ability.
Profane Ritual
Type of Feat: General
Prerequisite: Pale master 6, Spell focus: Necromancy
Specifics: By sacrificing his own lifeforce the pale master is able to summon an exceedingly powerful undead abomination (I.E Nightwalker, Doomguard, Greater Huecuva, etc).
The pale master receives 10d6 negative energy damage and must remain concentrated, lest he loses control of the undead.