The sentient hologram idea bothers me. With Data they establish that consciousness is only possible with a specialized positronic neural net that is extremely difficult to reproduce. OTOH holograms are programs running in the ship's computer. Ordinary programs, on ordinary (for Star Trek) computer chips.
Voyager is often written as though a hologram has some special physical properties that make it logically different from a computer program without a holographic projection. But I think it's clearly established in TNG and DS9 that holograms are programs in the computer controlling projected force fields and replicated matter and whatnot.
I know The Doctor sometimes runs on the mobile emitter instead of the ship's computer. And TNG did break its own rules with Moriarty. And arguably DS9 did too with Vic Fontaine. I don't mind because these occasional exceptions are fun! The Doctor is the best part of Voyager! Mostly it bugs me when they imply that every computer program is sentient (but only if it's connected to a projector!); or especially when they bring in photonic beings that somehow aren't projections controlled by a computer and holographic hardware?
Maaaybe you could argue that Voyager holograms are special because the bio-neural circuitry has some of the same properties as positronic neural nets. But I don't recall any explanation of that sort in the show.