Here's the thing with a "10th player" IC: they are always going to be inherently biased in some way.
- If they're as uninformed as a spectator, they're more likely to be game-solving and thus pro-town.
- If they know who PRs are, they're probably going to be subconsciously biased towards advice for those roles.
- If they know who the scum are, they're more likely to accidentally have advice for their exact situation that players can link.
- If they're as informed as the mod, might as well have the mod do the job, and it's generally considered that's not good.
If there's a desire to decouple IC advice from in-game players, I would say do it like this instead:
- Have a publicly-viewable document full of IC advice. Being an IC means you have the rights to edit this document.
- The mod, or a dedicated IC "hydra" account, reads the game and pastes/quotes/links to the IC document, in the game thread or the scum PT, at appropriate times.
- You could assign ICs to watch games, or have them free-float around at will.
Obviously this won't be as in-tune to the game as a player IC, and there's always going to be arguments over what to put in the repository.
Or, if the problem is just "ICs die too early", allow them to submit future posts to the mod, such as "post this if I die tonight" or "post this if I'm not alive at LyLo". The mod would make the post (as long as they approve that it is only IC advice and no reads or such) but very clearly attribute it to the IC. This obviously has its own problems (e.g. perception of being a treestump).