Wiggyboy
Oroborous
Then I suggest that Dominate Person does not go beyond Hold Person. Hold Person is a kind of "mark" for the length certain spells should last. Spells that essentially make you walking prey shouldn't last longer than a round per level. Dominate person could always "break" when you take damage, but its not "breaking" when someone has a few turns to lay traps around you, buff themselves up, buff up their friends, ask you to walk somewhere quiet and unobserved--and then count to three to slaughter you. Which tends to happens when people "rp" mind control spells.
The duration is actually considerably shorter than hold person. It's 3 rounds + 1 per 3 levels. That's, at level 9, 5 rounds. Compared with an extended hold person that would be 18 rounds for a level less of a spell slot. It's a 9th level spell countered by a level 1 spell, so I fail to see how giving it a larger duration is entirely too game breaking. I'm sure i'd much rather see a bit of RP put it into any PvP / Plot conflict using this spell compared with just casting 2 firebrands for the same spell cost and killing someone outright before they can react.
1) I wouldn't compare it to an EXTENDED spell since you're comparing apples to oranges. The spell should not last longer than Hold Person. It should not last LONGER than an Extended Hold Person at all for any reason. That makes this spell far superior to Hold Person. Its now a guarenteed kill spell that's even worse than the already over used Hold Person.
2) You may like the roleplay, but are not addressing the abuse the spell can get if its used for Mind Control. I'd much rather just get whacked by two firebrands instead of seeing my entire faction ripped apart because one guy with one spell in 20 minutes was able to Dominate a member of the faction and get all the information he had about it.
3) Saying its a "level x" spell countered easily by a weak "level 1" spell isn't convincing me either. Very few spells can not only decimate a rival in PvP--but decimate his entire faction as well by uncovering all its secrets, members, plans, goals, hiding places, all with one spell.
Just to sum up, the Spell can easily be increased to a round/level just like Hold Person and similar "stun" spells--Charm Person, Power Word, Stun etc--but it doesn't need to be vastly more powerful than those--especially in the hands of a person who uses it for "roleplay" because it is far too disruptive in a medium not carefully protected by a DM--and further with no counters.
Yes, I'm aware of the level one spell counter. However, in PnP you can block the spell with dozens of methods--which are entirely unavailable in NWN. I can think of many a PnP session where an NPC fell into our grasp; we went to use Dominate Person to learn more about him, the NPCs had cast a Gaeas on him that caused his head to explode when he started to talk, or some spell that allowed him to lie, or wiped his memory--none of which exists in NWN to counter this spell, or even mislead people who use it with a Contingency spell that causes the Dominated Person to actually be compelled to lie under the Spell unless the caster of Dominate wins a very high Spellcraft roll to notice the enchantment on his 'victim'.
Without all of that, the spell should not be used in a "roleplay" method in NWN.