My friend once made a Saproling deck pretty similar to this, except it was orinigally an Extended deck, and his goal seemed to be much more comboish, whereas yours seems a be a little slower but steadier stream of Saprolings. I'll give you some insight on his card choices, and you can decide if it's too different from your vision of the deck or not.
1. Haste
Having a source of haste for the elves (and druids, but I'll get to that later) can really speed things up. The two choices we boiled it down to were Lightning Greaves and Concordant Crossroads. A quick comparison:
Greaves
Pros: Doesn't give your opponents' creatures haste, can be a tad helpful in protecting a key creature (though that's usually not a big issue)
Cons: Costs 2, doesn't help you swing for the kill any faster
Crossroads
Pros: Costs 1, can help you win a full turn faster (Generation, Symbiosis, Verdeloth, attack, gg in 1 turn instead of 2)
Cons: Gives all your opponents' creatures haste as well (you mentioned playing in multiplayer, where this might become a problem for you)
Basically, if you're not worried about your opponents' creatures getting hasted, Crossroads is the better choice, as it affects your whole Saproling army instead of just helping out the elves. Essentially it's a metagame call, and totally up to you.
2. Cradle Abuse
The elves are nice acceleration, but when you really want to go broken and have fun with this deck, it's Gaea's Cradle that you're looking for. After you've played any sort of Saproling creation, the Cradle far outshines the Priest, and my friend built his deck based on abusing this fact. Krosan Restorer was essential to his build, and this being a Type 1 deck, I'd say a Candelabra of Tawnos would be a good choice as well. With a source of haste on the board, being able to drop a 3cc creature that immediately untaps a 10+ mana producing land is amazing. This is also what makes Crop Rotation excellent, as you can use it on a tapped Cradle and replace it with a Cradle from your deck. Who needs Dark Ritual when you've got 'G: Add GGGGGGGGGGGGGGG to your mana pool.'?
3. Skullclamp
It's not essential, but if you're going off super-combo-style, it helps to have as much draw as possible. It's also a lifesaver on slow draws when you can't get to 6 mana for CU, or you simply don't draw it. I think it definitely has a place in the deck, but the quantity is pretty flexible.
4. Saproling Supporters
Your Saproling warchief of choice is Verdeloth, who I believe is excellent. However, Nemata, Grove Guardian was the leader of choice for mi amigo, and he proved his worth in many a game. His Saproling creation is noticably less efficient (3-for-1 to Verdeloth's 1-for-1), but his other ability is the real winner. Its biggest advantage seemed to be the following situation, which came up fairly often:
Say on Turn 3, you play a Spontaneous Generation for 5, and that's all you can do. Next turn you topdeck a Cradle and go wild, creating 50 more Saprolings and dropping (Verdeloth/Nemata). Now, the problem is, only 5 of your Saprolings can attack, while your other legions must stand by idle. With Verdeloth, you'd have more Saprolings total, for sure, but you'd only be able to attack for 10. Put Nemata in his place, though, and you can sacrifice as many lackies as you feel like, easily being able to win this turn.
In the end, it's really just a matter of preference and style - do you want to win with an incredible horde of Saprolings, or do fewer but beefier Saprolings suit your fancy? One minor point, and I don't know what you're going up against or anything, but Nemata also helps you survive stupid things like Pyroclasms, Flamebreaks, Earthquakes, etc. Hey, it might come up sometime, you never know.
Want the best of both worlds? 1x Verdeloth the Ancient, 1x Nemata, Grove Guardian, and 2-3x Fierce Empath. Just pick whichever Tree-boy fits your needs at the time.
5. Regrowth
Sure, why not? 4GG to replay a Symbiosis is nothing when you consider you're doubling an already-doubled army, leaving you with a pretty ridiculous board. Also helps make up for the restriction of Crop Rotation, as replaying one of those is always fun - just make sure you still have a Cradle left in the deck when you do. Could be fun with Collective Unconscious as well, just make sure not to accidentally lose.
I think this post has gotten too long already, so I'll shut my trap now. But a few quick final notes:
- If you do decide to try the more broken-combo-ish route, Saproling Burst is pretty weak. 4G for, usually, three 4/4s doesn't help you much at all. When you're abusing the Cradle as much as possible, take quantity over quality anyday.
- If you want to splash red or white for Mutations, it shouldn't be too problematic, just switch out some Fyndhorns for Skyshroud Elves. They're slower, but provide all the mana fixing you'll ever need. Similarly, if you want to add blue, toss in some dual lands and maybe Quirion Elves.
- Never forget, this deck should always remain fun to play. Whether it's just the nature of the deck, or the look on an exasperated player's face when his T1 Fish deck loses to
Saprolings (and yes, this did actually happen. the guy was pretty pissed
), this deck is a good time.
Hope you maybe find something worthwhile in all that rabble. Ehehe..
Edit: Oops, it was an Extended Fish deck after all. But it was funny nonetheless.
