I wonder whether Someguy2000 will even bother to mod F4. He did post on Nexus some thoughts about his plans and F4, mentioning the voiced PC in particular as a restriction.
Regarding other restrictions, the four options limit could be circumvented (only partially) by having the fourth response be a pointer to the previous or next chain of three responses, and that works, but it's blatantly jury-rigged and shows the limitation of having only four options at any instance. Another method involves using notification windows for the dialogue interface, allowing for no limit to the number of responses at any instance, so I'd take that any day over the vanilla one. The character system doesn't fare any better, given the rigid perk ranks replacing skills, which makes acknowledgement of character builds always more limited. Adding new perks must be done outside of the perk chart using something such as an aid item in the Pip Boy, which is also jury-rigged. The more people try to compensate, the more apparent these restrictions are.
I would advise him to not even bother, given the state of the character system, primarily. If it weren't for it being what it is in F4, there could still be potential for quest mods with the same or similar degree of role playing.