Multi-elemental Wizards?

Most of them use all elements. They start off maxing the 3 starter skills (one of each element), but tend to focus on stone barrier/water shield and less so on pyroshell. Then you get divine pyrogram (some love it, some hate it, it's not particularly useful before getting sutra). Dragon's Breath is for zhen, so once you get it leave it low leveled until 60+ where you can then decide what level you need to keep up with other people in your server.

Then the next level of elemental skills: Will of the phoenix (some love it, some hate it, it's a wonderful skill to max, but few ever do), sandstorm (everyone loves it, always level it), and frostblade (not a priority).

The one after that: Emberstorm (don't bother unless you're 90+ with the hell book imo), force of will (excellent skill, useful even at level 1 + useful later for different reasons, people level it up when they can but attack skills come first), glacial snare (hardest hitting single-target mage skill, 80% slow, what's not to love? it has a beastly cooldown of 15s)

And lastly, the ults: Blade Tempest (go-to spell for killing robes throughout most of midgame, most level this first because it has PvE value too for killing increased magic resistance mob), BIDS (prettiest skill a mage ever gets imo, most don't level it til 80+, slows what it doesn't kill), Mountain's Seize (very high probability of stun, the damage difference is not that high between BIDS and MS.. some prefer it, 1s longer channeling). Ults are a matter of preference.

All that being said: With masteries, most tend to raise earth first because maxed earth mastery+earth skills = 2-3 shotting water mobs. The reason some people prefer MS over BIDS is partly because they have high earth mastery and low water mastery, so the dmg diff is even smaller. Fire usually comes next, then lastly water specifically for Snare and BIDS.

Skills people skip over leveling the most: crown of flame, pitfall, hailstorm (tho it can be nice to have at 80+ for tw), emberstorm

at very low levels we're forced to focus only few spells (regardless of the element) due to lack of spirit. at mid levels the fire/earth/water masteries make it harder and then most prefer to neglect 1 element completely to manage keeping other elements and masteries up to the highest possible level. even then you'll be able to upgrade only few spells... at lvl 59 you should pick all 3 AOE ultimates and then focus only the one you like the most.

right now, at lvl 80, i can barely keep my ice dragon up to my lvl due to lack of spirit. other lvl59 spells are terribly neglected. i assume only at 9X it will change.

I remember a few weeks ago someone said they were a fire-mage, every was going wtf does that mean?

I've never seen this. BM's have to specialize in a weapon because of the amount of skills they have. Wizards don't have that many so they can use all three. One of the greatest parts about being a wizard is that we can trump three out of the five elements (Metal, Water, and Fire).