Summertide and Wintertide Phial: Combination like the Move Quickly/Slowly boots, the Phial of Surging Seasons!

[Kain Yusanagi]

The Wintertide Phial and Summertide Phial are pretty neat items, and I've always thought that they should be able to be combined.
Just so everyone's aware of their stats as of this post, their stat blocks are as follows:
Summertide Phial
Deals 15 Light damage and lights tiles in radius 1 on melee hit
+30% light resistance
+10% light damage
+5 light radius
+10% healing mod
On use, dispels darkness and reveals tiles within radius 20, power determined by willpower. (10/15)

Wintertide Phial
+2 Light radius
+7 infravision radius
On use, dispels X mental effects, where X is determined by magic. (40/60)

As you can see, while Summertide got a bit of a buff sometime in the past (it never had the bonus light damage), Wintertide has been left in the lurch; as such, I thought that combining the two of them to make something like "Phial of Surging Seasons" would be neat. As for how to combine them, you could give them an ability that is inactive unless you have the other in inventory, to trigger the combination, without interrupting the on-use ability (Morrigor already has a similar setup, with it having both the Soul Purge ability and the soul talent, which takes the place of the weapon talent, as one such example).

Here's one idea for statting it out that I had. Nothing too strong, but gives it more desirability for classes that don't melee, too.

Phial of Surging Seasons
Deals 20 light damage/20 darkness damage in radius 1 on melee hit
Deals 10 light damage/10 darkness damage in radius 1 on ranged or spell hit
+35% Light resistance/+35% Darkness resistance
+20% Light damage/+20% Darkness damage
+10 light radius/+10 infravision radius
+10% healing mod
+20 stealth
On use, sends out a wave of light/darkness in radius 10 that dispels darkness/blinds foes and clears N mental and magical effects (where N is determined by whichever is higher between magic and willpower), and switches stat blocks to the second variation. For 5 turns after switching, gain +20% Light penetration/Darkness penetration. (30/50)

What do you think?