I'm most likely going to sound crazy saying this, but I DON'T recommend getting a weapon to replace the JJP right now.
I think you should save your leftover money(Which I calculated to be about 400k, give or take 100k) until you have enough for a
Fungus Ray.
Why? Because your only water in the set is from the Commander Blade. Fungus Ray + Commander Blade would be a killer combo. In addition, it gets a LOT through common shields not named Leaf Shield. It gets 3 through both burrow and sink(8 when combined with WoR).
In addition, there is little water blocking weapons out there that people ACTUALLY use. And don't tell me "But
Leaf Shield is on every set! It's Gonna get blocked!", because in that case your
Commander Blade should be replaced with
Mystical White Cloak becuse the Cloak does more against it.
Untill you have the money for it, put a
Scarab Ring in the slot.
Of course, that's just one person's opinion.
EDIT: CadaverGrey, you made a typo in the poll title. you put "Shoudl" by accident.
Since you're considering a bit of 2p along with 1p and the amount of icons are nearly the same, I'd say don't really factor 1p into this since it doesn't affect anything a grand scale with you look at both. With the weapons you seem to be focused on using the main thing in 2p you'll be looking at is what do yo want to draw out? Light is heavily defended against with dual duties, and you don't have much of a chance of getting the light through even with Lenny Chatter, a fine ability I'm quite fond of myself

. Earth on the other hand is mainly only blocked by MoC, or else a Leaf Shield, which isn't so commonly used anymore as it used to be, and it doesn't attack. While EoE does get entirely blocked, you don't have to use it all the time. Use it so you draw out their Leaf Shield if they aren't using a MoC and use a different weapon so they waste a turn. To top it off you get water, which is hardly ever blocked aside from Leaf Shields which you probably won't see at your level too much now.
Very nice, guys!
I have little fear about water being blocked.
Leaf Shield,
Hobans Hat, and
Frozen Wand of Crystal would be immediate problems, yes. But I am actually more afraid of
Mask of Coltzan and
Ghostkershield more than anything. Thus you can see the ultra heavy concentration of fire and air icons, with a considerable amount of physical as my back up icon against most dual duties (except
Yooyuball weapons and
Winged Scarab).
I would love to have a bit more water in my attack, though, so that is why I am considering weapons like
Pike Pike,
Essence of Esophagor and
Icy Battle Duck (the last being Rabid's suggestion).
I actually like the reasoning behind
Fungus Ray and I think I will consider it. The reasons for the use of
Essence of Esophagor are nice as well, though still, it will face problems against MoC.
Hmm... still a few days worth of training left so plenty of time to consider things. Keep em suggestions coming!

I'm gunna slightly alter my suggestion. I think you should still go EoE right now (Earth is still > Light IMO) But you should save for an Icy Battle Duck after you get all your other weapons. It would be a killer backup weapon. Air is hard to block, and water is too. As far as leaf shields, there isn't really any running around. Hobans Hat, maybe at the levels you'll be battling at. And the Wand, well, there is hardly any at the 55 boosts and I assume at the higher levels there probably won't be any.
Now that I'm reminded of it IBD would be a good option, better than the EoE. Even though last time I looked at the TP it was 2.5mil, you should be able to get it for cheaper. It's been consistently around 1.4-1.7mil for the past year until just a few months ago, so I do beleive you're just dealing with an inflated price. I used one for awhile until I semi-retired and no matter the dual duty (no Hoban's Hat at the time) my icons went through. I had a nice P-Kiln/ IBD combo that was pratically my main attacker. After the opponent used burrow/sink they couldn't really do anything. It's a very fun weapon I'd have to say. If you can find a duck for a decent price, go for it.
I would also like to point out the from a defending standard, the Fungus Ray get's the same amout of icons through MoC as the EoE if you go that route, but otherwise the extra icon and dark icon mix should help in most cases.
On Skeletal Fire Gun:
My intital thoughts on the weapon were that it was amazing. It had a solid 8 icons 6 of which go through GSheild and other dual duties besides scarab ring. However, the times that I would consider using it would have been when another dual duty is already killing another one of my weapons, such as AFC, MoC or GoC. With your current set, it appears that your 2 main constants are WoR and MoC so the main defensive weapons that you need to worry about are the 5 light defending icons which will still take a large enough chunk out of SFG to make SFG do less icons than the 5 lihgt defending dual duty (although it is even against SoTD). Scarab ring also does a net 12 icons against this combo. It also only sends 6 icons through GSheild, but that seems to be its main application here, and Chili Sword does a better job of that. Although it would leave you open to a turbo flame reflector + any other item, I have rarely seen it equipped. If they switch to turbo flame reflector + another item, it also gives you a chance to switch back to the WoR + JJP to hit them unhindered, while they have wasted a weapon slot, and probably did not do as much damage as you just did to them.
Actually, sovereign, my main weapons with the set up I have would be the WoR and JJP. But the fact that it won't do in a 1-player and low intel 2-player scenario was the reason I asked for opinions on what to switch with the JJP

. The SFG is more of a back up than anything else. I just love the idea of using ist TOGETHER with the MoC, for a near mono-iconed attack of fire, and with so little shield to worry about (except
Clawed Shield. If that happens, I can easily switch back to my WoR and second main, heh

).
So right now, the second main is my biggest concern, but looking at how things look, the IBD is looking mighty appealing. And I seriously do not mind overpaying for it
Thanks for your thoughts!
Modification on my advice: Get an EoE while you wait for the Fungus Ray.
I just realized that if it's your second attacker, scarab ring ain't doing enough.
So EoE--->Fungus Ray(When you have the money)