What about adding a Gea's Cradle in there for more manna... check out my Sap deck for some cool idea's you might like
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Clasic Deck, I love it... Replenish is awsome... maybe add Capsize for a bit more control..
Try Songs of the Damned, Drain Life, and Fluctuator, with a bunch of cycling creatures to feed the songs... it's pretty cool you can cycle through your entire deck and play songs for the killlll... nobody ever sees that coming...
Yeah?
What about puting Niv-Mizzet, the Firemind dragon in there? he's only 6 mana and your U/R manabase is pretty balanced. maybe take out 2 giant solifuge and add in 2 dragons... this'll make the card draw turn into burn... I'd find a better sub for the Raging goblin too... maybe just leave 2 in there an 2 of something else... they're just too weak come turn 4ish... Char does sound a bit weak maybe mainboard the Volacnic hammers instead.