Love this class. I'm trying one out right now. However, I have a few issues currently with the Arcanist:
1. The Arcanist Reservoir Point (ARP) Progression runs dry too quickly at low levels.
At Level 1, Arcanists have 1 point to use per day. Compare this with Wizards or Sorcerers—across the board, they have abilities that are 3 + the Int/Cha modifier uses per day.
My primary proposal is to make ARPs refill each day according to this pattern.
An Arcanist would begin with 3 ARPs, then get an additional ARP at Level 3 and at every third level afterward (6, 9, 12, ...).
Compared with the current system, this would give low-level Arcanists more ARP, but the progression is slightly slower so that it evens out at Level 12, then falls slightly behind. At higher levels, between cannibalizing Level 1 spells, using exploits to gain ARP, and so on, there should be enough ARPs to go around.
2. ARP Storage needs fixing.
At Level 1, an Arcanist can store 2 APR a day. By Level 20, she can store 40, but will only get 11 per day. That's a massive jump.
I propose that an Arcanist can store the same number of ARP she gets each day, plus 3 (or 5 maybe), plus her Charisma modifier if greater than zero.
In addition to this, modify the Arcanist Exploits that steal ARP so that they also expand ARP storage by 2 each. This will allow some extra leeway.
The raw progression with no Charisma bonus would look like this.
3. Counterspell Can't be Used When Needed
Counterspelling is really needed when facing an enemy spellcaster. Often times, this spellcaster will be higher level than the Arcanist. Add to this the slower spell progression of the Arcanist and it means that the Arcanist will usually not be using counterspell.
Rather, allow Counterspell to work on any spell, but with an Exploit Penalty of DC+3 for spells of equal CL, with an additional +3 for each level higher. Also, I feel the Arcanist should add her Charisma modifier to the dispel roll.
For example, a Level 1 Arcanist tries to counterspell a CL 4 spell, such as Glitterdust cast by a L4 Wizard. The dispel check DC would be 11 + the spell's CL + the Counterspell Exploit Penalty = 11 + 4 + 3*3 = 24.
The Arcanist would roll a 1d20 + CL + Charisma modifier. That's 1d20 + 1 + 4 at 18 Charisma (which might be accurate for an Arcanist built for counterspelling).
Here's a chart outlining the rates of success based on the difference in CL and Charisma Modifiers.
This has has the following effects:
a. Arcanists who aren't built specifically for counterspelling can still take the exploit and be somewhat successful with it. They'll have a 35–50% chance of countering equal-level wizards casting weaker spells—mook casters—and a 15–30% chance of countering mooks' most powerful spells.
b. Arcanists built for counterspelling can deal similarly with wizards that are one level higher: 35–50% chance of countering weaker spells and a 15–30% chance of countering the most powerful spells.
c. Arcanists who have invested a lot into counterspelling will be able to deal with wizards that are two levels higher: 35–50% chance of countering weaker spells and a 15–30% chance of countering the most powerful spells.[/list]
If those odds are too good for the Arcanist, change the Exploit Penalty to DC+4 for spells of equal CL, with an additional +4 for each level higher.
4. Not All ARPs are created equal.
ARPs can fuel either powerful exploits or comparatively lack-luster exploits (I'm looking at you, blaster exploits). This means the value of an ARP is extremely variable.
One solution: Weaker abilities (e.g. the blaster exploits) function at 3 + Cha modifier uses per day. This allows them to be used frequently for dealing damage (similar to Wizard/Sorcerer School/Bloodline powers).