Hmmm, ok, so DC 20 Heal with 2 Con damage?
I can go for your ideas on remove disease, heal, limited wish, wish, and miracle. Bend reality is good (with a note "in campaigns using psionic rules"), but psionic chirurgery doesn't remove physical diseases, so I'd leave that off. I think I'd leave the "boring it out" for flavor. I can also agree with your take on banishment and dismissal.
My thinking was since
psionic chirurgery allows the healing of ability damage, the rewiring of nervous systems and cures energy drain and insanity it ought to be able to undo all the nerve and blood vessel connections between the worry-wart and its host - although the warts themselves may remain physically, the
chirurgery effectively "severs" the
nibish-riule from its host.
Upon reflection, how about if the surgical DC increases over time, as follows:
Worry-warts are very hard to get rid of once they infest a host. If it is in the process of merging with a host, the worry-wart can be surgically excised by a Heal check with a DC equal to the number of days it has spent merging (minimum DC 20), each surgical attempt does 2 Constitution damage to the host. A merging worry-wart can also be removed by the spells remove disease, heal or limited wish.
A merging worry-wart can also be removed by any method that removes a worry-wart that has completed its symbiotic network. Complete networks cannot be removed surgically, but a properly worded wish or miracle spell can cause the wart network to vanish. The spells banishment and dismissal can force the extraplanar portion of the nibish-riule away and sever it from the network if the nibish-riule fails a Will save (it has a Will save of +10 since the complete entity has to be exorcized). If the campaign used Psionics, the psychic chirurgery power can be used to sever the nibish-riule's nerve-links to the worry-wart network. Severing the nibish-riule from a symbiotic network leaves its unsightly warts behind, but they become inanimate and eventually heal and fade away like ordinary warts.
I think I'd leave the "boring it out" for flavor.
I'd like to mention the "plaster option" in the text though:
After 2d10+20 days the symbiotic network is completed with a total of 1d4+2 beauty marks. The worry-wart gains the ability to communicate with its host telepathically and grants its host the benefits of its constant vigilance ability. Each "beauty mark" of a complete network is an eye the worry-wart can open to view its surroundings. These eyes can pop out on stalks to peer around itself, the flexible eyestalks can easily curl round to stare at the host's body or face. The stalk can extend up to a foot in length, support its own weight and wriggle under clothing to peer out of cuffs or collars if necessary. Placing a well-secured plaster or patch over a wart can prevent the eye emerging, but this causes the nibish-riule to constantly complain it cannot see properly.
Yes, let's treat them like a hive mind for flat-footed.
Do you think we can fit that into the Constant Vigilance SQ?
Upon reflection, it's no different from an ally calling "it's behind you!" since the host doesn't share the worry-wart's senses. It's nowhere near the complete situational awareness of a proper hive mine.
What about flanking? I suppose the worry-wart's ability to warn the host of an incoming attack might have some benefit in that area, although not full immunity á la All-Around Vision.
How about:
If the worry-wart is aware of a particular danger, its host is too. If the worry-wart is not flat-footed, neither is its host. Opponents who flank the host have their flanking bonus reduced to +1.