Well, at first glance, I'd probably up terminate to 4, and lose one Into the Roil. This gives you an extra DEFINITIVE out against creatures, and combined with the fact that you have 3 Calcite Snappers instead of the usual 2, and that you have 2 Earthquakes instead of the usual 1, this lets you move Jace Beleren to the main, fighting Jace-based decks by playing yours a turn earlier, and also makes for a better card-draw spell than See Beyond. This also adresses the issue that you won't tap out turn two, leaving yourself open to Putrid Leech, which WILL screw you over (hence, 4 Bolts).
I think you pretty much nailed the rest, and Lavaclaw Reaches is good to bait out Spreading Seas in case you want to win on the back of Tar Pit, and ALSO if the game goes long enough that you're both stretched thin, since it can take out a pretty big chunk of life out of an opponent. This also means you have a way of beating Howling Mine decks, as you have permanent threats to keep swinging, forcing them to spend their fogs and then knocking their life in large chunks, so I wouldn't be so quick to dismiss its merits.
Moving on to the board, I understand Consume the Meek, and it really IS
goo at what it does, but their main usefulness (knocking out manlands) you can accomplish with Seas, so I'd cut it for a singleton Consuming Vapors. Removes 2 guys, give you a little life cushion (considering your removal suite, you can narrow it down to make at least one profitable use of Vapors) and is INSANE against Polymorph decks. You can also lose a Smother (you removal kills pretty much every target it'd be used on), leaving 3 open slots in which you can fit in 2 Relic of Progenitus if Vengevine is giving you a headache, and probably another singleton, or a secon Vapors, or the Into the Roil we removed. OR, leave in Smother if you like it. Or Bituminous Blast?
