increase maximum strength
How big should the biggest creature be?
If Strength = Potency, then the biggest possible Strength is 4.
This helps balance the system, but prohibits creating horrifying monsters and giants, which are fun.
(Side Note: Potency was a limit, rather than a bonus, to ensure that fighters would always prefer to buy more Strength than to buy magic which increases Strength)
It also seems odd that mages can take an animal of any size - dogs, rats, et c., and they all reach the same size in the end.
New Suggestion
Strength = Potence + 1/2 Strength
A fighter with Strength +1 might spend 20 XP to gain Earth 1 + Water 1 (and therefore Polymorph 1), increase his size to (1 + 1/5 =) +2 for an interval, but it would be better to just increase Strength.
Polymorph Potency 2
| Basic Str | Final Str |
|---|---|
| -2 | 1 |
| -1 | 2 |
| 0 | 2 |
| 1 | 3 |
| 2 | 3 |
| 3 | 4 |
| 4 | 4 |
| Max | 4 |
Note that even if polymorph spells stack (perhaps because someone has made a permanently durable spell, with 5 MP), they have a maximum.
Polymorph Potency 3
| Basic Str | Final Str |
|---|---|
| -4 | 1 |
| 1 | 4 |
| 2 | 4 |
| 3 | 5 |
| 4 | 5 |
| Max | 6 |
Polymorph Potency 4
| Basic Str | Final Str |
|---|---|
| 1 | 5 |
| 2 | 5 |
| 3 | 6 |
| 4 | 6 |
| Max | 8 |
General Penalties
There should probably be some general penalties associated with such radical shape-shifting. Maybe any one of:
- -1 Dexterity
- -1 Dexterity per potence (too harsh?)
- 1 Fatigue per Potence
- 1 HP lost per spell potence (so creatures must heal between spell-casting sessions)
I'm rather a fan of that last one - it stops almost all potential for abuse, but allows great big monsters to be unleashed.