On the contrary, most mages do not bother with Improved Arcane Missiles. You shouldn't be getting hit anyway.
Here's my own variation on an Arcane/Fire levelling build. The main tactic is open with Pyroblast, then go to town with Scorch and Fireblast, with the occasional PoM-Pyro to spice things up. Blast Wave can easily be put into Slow instead; both talents have their merits. Once you get high up, Arcane Blast gets thrown in (though I don't have any experience with the spell, so I'm just going from others'). Top priority for gear would be int, +crit and +spelldamage.
Here's my own variation on an Arcane/Fire levelling build. The main tactic is open with Pyroblast, then go to town with Scorch and Fireblast, with the occasional PoM-Pyro to spice things up. Blast Wave can easily be put into Slow instead; both talents have their merits. Once you get high up, Arcane Blast gets thrown in (though I don't have any experience with the spell, so I'm just going from others'). Top priority for gear would be int, +crit and +spelldamage.
Earthen Ring-EU:
Taelas -- 60 Human Protection Warrior; Shaleen -- 52 Human Retribution Paladin; Raethal -- 51 Worgen Guardian Druid; Szar -- 50 Human Fire Mage; Caethan -- 60 Human Blood Death Knight; Danee -- 41 Human Outlaw Rogue; Ainsleigh -- 52 Dark Iron Dwarf Fury Warrior; Mihena -- 44 Void Elf Affliction Warlock; Chiyan -- 41 Pandaren Brewmaster Monk; Threkk -- 40 Orc Fury Warrior; Alliera -- 41 Night Elf Havoc Demon Hunter;
Darkmoon Faire-EU:
Sieon -- 45 Blood Elf Retribution Paladin; Kuaryo -- 51 Pandaren Brewmaster Monk
Taelas -- 60 Human Protection Warrior; Shaleen -- 52 Human Retribution Paladin; Raethal -- 51 Worgen Guardian Druid; Szar -- 50 Human Fire Mage; Caethan -- 60 Human Blood Death Knight; Danee -- 41 Human Outlaw Rogue; Ainsleigh -- 52 Dark Iron Dwarf Fury Warrior; Mihena -- 44 Void Elf Affliction Warlock; Chiyan -- 41 Pandaren Brewmaster Monk; Threkk -- 40 Orc Fury Warrior; Alliera -- 41 Night Elf Havoc Demon Hunter;
Darkmoon Faire-EU:
Sieon -- 45 Blood Elf Retribution Paladin; Kuaryo -- 51 Pandaren Brewmaster Monk