I'm not sure if I'm missing something here... but it doesn't look that good. Heres why:

Zombies are pretty useless without proper gems. I'm not sure if the point of this chest is focused on zombies or spectres. If it were supposed to make strong spectres, then it won't since there are 50% less spectres and 30% reduced damage. If it were focused on zombies, the zombies won't have the gems necessary to do damage unless you mean to have zombies in a 6L, then what is the point of this chest.

While a minor inconvenience, players don't like to constantly raise spectres. Furthermore, many gems will be unused since not all gems are compatible with all spectres. For instance, a caster spectre would have no use for multistrike or melee physical damage.

As for zombie modifiers, I haven't played during prophecy league but I'm pretty sure any minion modifiers already apply to both zombies and spectres. Unless you mean for the zombie's mods to stack on top of the spectres, in which case that can potentially be super OP if you were to use a 6L chest to support spectres and then another 6L weapon with support gems meant solely to support the spectres. In doing so that would effectively give the spectres a 10 link.

Lastly, could this chest's drawback be potentially nullified by Null Inclination's cast minion spells on kill? If so, that'd be pretty op since your chest says "also apply" to your spectres not "applies" so your zombies would still retain its modifiers and your spectres would have a 10 linked.

Please correct me if I was wrong about any mechanics. I haven't played since perandus so hopefully I haven't forgotten too much about the game.