[Infares]

I'm currently a summoner, and I got through the last act of normal and into the first act of epic using Maxed Eruption, Maxed Plague (with synergies) and just enough ranks in regrowth to reliably heal half my HP at any one casting, exactly 1 point in Stoneform (Since Regrowth is better as a source of healing, the six second invulnerability is static across all levels so for me, IMO only 1 point is perfect. Hell, just throw up stoneform and use a potion, you get more potions than skill points.

I'd stay off of molten rock, most mobs won't last long enough from your eruptions to actually make molten rock worthwhile. Aside from your 1 point in stone form, and maxing Eruption, Volativity, Earth Enchantment, and Brimstone, as far as I'm concerned if you intend to remain petless everything else can go into your second tree.

VS bosses, you'll proly end up just dumping an Eruption at their feet, although if I were you I'd save Stone Form for when you actually need it and micro your character around the boss' ranged attacks. That's the great thing about eruption is that it lays the smackdown six seconds at a time so you only need to stop to drop it and then run around, much less mana and micro intensive than Volcanic Orb IMO, you can fire it and continue running around etc.

If you're going to remain petless, I'd do some research on your potential subs that benefit you as a pure caster, obviously Storm, Spirit, or Nature will end up being your sub, and I can vouch for the power of Plague tree's synergy with Eruption kiting, mobs get slowed, mobs get some life hacked off, mobs take poison damage, and last but not least, mobs lose 39% of their elemental and damage resistances, (via Susceptibility) which is especially good vs mobs that are strong vs either the fire or physical component of Eruption, making them take a lot more damage in the long run.

Plague with all the trimmings has both offensive and defensive impact on your eruption kiting strategy, and the ability to spot heal yourself for potentially 2000 or more hp at a time is a strong argument in favor of being a summoner that doesn't, er, summon, IMO. Recently tried respeccing back into pets and at 35 I'm to the point where I can feasibly get maxed wolves sans Maul which are nigh immortal and good damage sources, or continue petless. I will probably opt for the latter until I can thread the wolves into my current strategy, once I have EE and Brimstone maxed and Volativity, Strength of the Pack from wolves will actually improve the physical damage I do with my Eruptions (on top of getting a bonus from brimstone and Susceptibility as well) but I'll ahve to stand right next to the wolves while I cast. Positive side to that is of course they'll be doing some burn damage with EE/Brimstone and if I can later afford to get them Maul maxed they'll be pumping out the DOT damage with bleed and burn.