I really didn't meant to discourage you. Personally I try to stay as close to PnP rules as possible (though there are some exceptions - ie. Witch class). Frankly I haven't played NWN2 much and don't even know how Kaedrin implemented the class, but if it's fun to play, maybe it's worth to be implemented in NWN too?
No worries, it wasn't a discouragement but it did make me take a look at what I had thought was the class and what it really was. Here's Kaedrin's writeup on the class-
Requirements:
Feats: Dodge, Mobility.
Weapon Proficiency: Bard, Elf, Grey Orc, or Martial.
Base Attack Bonus: +3
Skills: Concentration 6, Spellcraft 6.
Spellcasting: Able to cast 3rd level arcane spells.
Spell Known: Haste
Class Features:
HD: d6
BAB: High
High Saves: Reflex, Will
Weapon and Armor proficiency: None.
Skill points: 4 + Int modifier
Class Skills: Bluff, Craft Weapon, Craft Armor, Craft Alchemy, Concentration, Diplomacy, Listen, Lore, Parry, Spellcraft, Spot, Tumble.
Class Abilities:
Level 1: Bonus Feat: Spring Attack, Swift Surge (+1 AB, +1 Dodge AC, +1 Reflex Save), Arcane Spellcasting Progression
Level 2: Blurred Alacrity
Level 3: Residual Celerity
Level 4: Arcane Reflexes
Level 5: Evasive Celerity
Level 6: Fortified Hustle
Level 7: Bonus Feat: Uncanny Dodge, Swift Surge (+2 AB, +2 Dodge AC, +2 Reflex Save, +d6 damage)
Level 8: Diligent Rapidity
Level 9: Perpetual Celerity
Level 10: Innervated Speed, Swift Surge (+2 AB, +2 Dodge AC, +2 Reflex Save, +2d6 damage)
Arcane Spellcasting Progression: At levels 2,3,5,6,8, and 9 you gain new spells per day and an increase in caster level (and spells known) as if you had also gained a level in an arcane spellcasting class to which you belonged before adding the prestige class level. If you had more than one arcane spellcasting class before becoming a swiftblade, you must decide which class gains the increased casting ability.
Spring Attack: At 1st level you gain the bonus feat Spring Attack.
Swift Surge: Your body is augmented with the residual energy of previous haste castings. You gain a +1 bonus on attack rolls, a +1 dodge bonus to AC, and a +1 bonus to Reflex saves. At 7th level, these bonuses increase to +2 and you deal an extra 1d6 points of damage. At 10th level you gain 2d6 points of bonus damage. These bonuses stack with the bonuses gained from the haste spell.
Blurred Alacrity: At 2nd level, your understanding of the haste spell makes you difficult to target with melee and ranged attacks. While under the effect of a haste spell that you cast yourself, you gain concealment (20% miss chance). This miss chance increases by 10% at 3rd, 4th, and 5th level. The effect of this ability does not stack with blur, displacement, or similar spell effects.
Residual Celerity: At 3rd level, your body retains more of the energy imbued by the haste spell allowing it to last longer. When casting the haste spell on yourself the duration is increased by 3 rounds.
Arcane Reflexes: At 4th level, you infuse the energy of previous haste castings into your natural reaction time. This grants the bonus feat Improved Initiative.
Evasive Celerity: At 5th level, your knowledge of the haste spell makes you difficult to target with spells. While under the effect of a haste spell that you cast yourself, you gain a Spell Resistance equal to 10 + character level. The effect of this ability does not stack with other effects that grant spell resistance.
Fortified Hustle: At 6th level, you learn how to intuitively absorb the haste spell into your body. While under the effect of a haste spell that you cast yourself, the effect becomes extraordinary rather than a normal spell effect, and therefore cannot be dispelled by any means.
Uncanny Dodge: At 7th level you gain the bonus feat Uncanny Dodge.
Diligent Rapidity: At 8th level, you automatically overcome magic and mundane obstacles with the haste spell. While under the effect of a haste spell that you cast yourself, you can move and attack normally, even under the influence of magic that usually impedes movement, as the freedom of movement spell.
Perpetual Celerity: At 9th level, the haste spell lingers even longer in your body before it dissipates. When casting the haste spell on yourself the duration is increased by 6 rounds.
Innervated Speed: At 10th level, your mastery of the haste spell seems to bring the world around you to a standstill. This effect is comparable to the slow spell with a 100' radius effect and lasting 10 rounds. This burst of speed is available for use once every five minutes. The DC of the ability is 19 + the higher of your Int or Cha modifier.
Here are the feats I see being a problem-
Arcane Reflexes-
You're supposed to get your primary casting stat bonus to initiative. I've seen nothing that will allow you to adjust initiative in that way. Kaedrin grants Improved Initiative which isn't too bad. Low levels you do better, higher levels it's weaker.
Evasive Celerity (Ex): At 5th level, your knowledge of the haste spell makes you difficult to target with spells. While under the effect of a haste spell that you cast yourself, individually targeted spells have a 20% chance of failing against you. This spell failure chance increases by +10% at 6th, 7th, and 8th level. The effect of this ability does not stack with blink or similar spell effects.
Here's one that has me perplexed. Maybe I've missed a function in NWN or the PRC but I don't know of any way to support a miss chance for spells. I know it can be done for attacks. Kaedrin gives spell resistance though I'm not sure if that's the best solution.
Bounding Assault: At 7th level, you gain Bounding Assault (see page 75 of Player's Handbook II) as a bonus feat. You need not have the prerequisites normally required for Bounding Assault to gain this feat. If you already have Bounding Assault, choose a different feat for which you do meet the prerequisites.
(Bounding Assault- When using the Spring Attack feat, you designate two foes rather than one. Your movement does not provoke attacks of opportunity from either of these foes. While using an attack action with the Spring Attack feat, you can make a second attack with a -5 penalty. You can use both attacks against one of the opponents targeted with this feat, or split your attacks between them.)
Another one that might be hard to implement. Kaedrin gives uncanny dodge, even though in NWN2 Uncanny Dodge is broken and doesn't work. It'd be more beneficial in NWN1.
Perpetual Options (Ex): At 9th level, you can perform even more actions with the haste spell. Instead of making one extra attack at your highest base attack bonus while under the effect of a haste spell that you cast yourself, you now have the choice of making one extra move action or one extra standard action. For example, you could make three consecutive move actions with this ability, two move actions and one standard action, one move action and two standard actions, a full attack action and a move action, a full attack action and a standard action, a full round action and a move action, or a full round action and a standard action.
Is this even possible with the limitations of NWN? Kaedrin increased the duration of haste by 6 rounds.
Innervated Speed (Ex): At 10th level, your mastery of the haste spell can bring the world around you to a standstill. Any time you prepare or spontaneously cast haste in a 6th level spell slot, you can subsume the spell at the moment of casting instead, increasing your speed so greatly that other creatures seem frozen in time, as the time stop spell, but for one round. See the spell description on page 294 of the Player's Handbook. For each spell slot level higher than 6th level, you can extend innervated speed by 1 additional round. For example, a sorcerer could subsume haste in an 8th level spell slot to create three rounds of innervated speed. You cannot subsume a new haste spell until the original innervated speed duration expires and your turn ends. Moreover, you cannot subsume a metamagic version of haste.
This might not be as difficult. My thought was to implement it as haste/timestop combo spell. There would be a 6th, 7th, 8th, and 9th level spell, each with the same effect but with one additional round of duration for each level. The problem comes in making sure other classes don't get their hands on it. I figure I could either have a check for 10 levels of swiftblade or maybe there is another way of getting the spell to only this class?
The rest is simple enough I think and as said would mostly require changes to the haste spell itself. The changes Kaedrin made mostly fit the flavor of the class, except the uncanny dodge. Mind you, the thought of a rapier wielding, weapon finessing, uncanny dodge elven wizard/swiftblade/Champion of Corellon is tasty to me still.