TLDR: Necromancer Gishing could be good and it gets close but its various feats and support for the playstyle fall flat, usually due to poor scaling and lacking power, personally i think the best step forward would be to give it a Warpriest style Subclass that gives it a better base and to buff and alter the feats to be stronger.
The Long: At a Base its chassis isn't the best for Melee, only light armour, simple weapons, standard caster progression, its got a good bonus because of the spell list that has some nice buffs but generally you have to spend a lot of feats fixing these innate deficiencies, so for smoother play and especially early level play (which is where melee necro is at its weakest) a Warpriest subclass to fix this would sort all of these issues.
and now Feats
Reaper Weapon Familiarity: this is an Ancestry Feat in the trenchcoat of a Class feat, what on earth is it doing here? i don't have any feedback other than just delete this and replace it with something else because it is entirely redundant with ancestry and general feats, Class feats should generally be better than both of those things.
also given that most of the weapons are strength based, it kinda highlights how much a Melee Necro needs a way to get at least Medium armour (also i like fully armoured Necromantic Death Knights)
Draining Strike: this is pretty good and i like it, however it does have a scaling issue and an action economy issue, if you have already setup a thrall to destroy with this then all is well but as a two action attack its pretty bad compared to most other two action attacks, personally i think their should be a way to pump a focus point into it (or just make a separate focus spell to make a big strike or something) to give it a boost at later levels.
Osteo Armaments: admittedly i don't entirely see the point of this feat, its awesome on a thematic level i love the idea but If i wanted to focus on Melee i would already have a weapon with runes, so i would be just spending actions on something i don't need and is slightly worse, at best if Enemy resistances are being a pain but you are still a spellcaster and have ways of getting around that, its too cool an idea to just scrap but it needs to do something better than just be a backup plan imo
Level 12: while not strictly a gish feat, they all to some degree make The Necromancer more tanky which is appreciated, no real complaints here
Bind Heroic Spirit: this is a level 18 feat, good Christ that is bad, i get it, its a focus point version of 9th level Heroism that spawns a thrall when you strike, but this comes FAR too late in the level to be meaningful and, this feat should come far earlier and should scale with the player instead of just being at max level only, also i think it should take a note from Animists playbook and add damage instead of adding to saves, attack increases enable melee, damage incentivises melee and all that.
I've seen this feedback pop up a few times and i hope Paizo takes into consideration as i really like Gishes and Necromancer is so close to being a good one it just needs some love
