I’m making a metorb Sorc, and i’m maxing out or am going to max out fireball, meteor, fire mastery and frozen orb, but should i max out fire bolt or cold mastery? Personally i like Meteor a lot, but fronzen orb is easy to use but is weak.
Also would a meteor sorc (as in maxing out meteor and it’s synergies) be viable in hell with sunder charms against fire immunes?
DUAL ELEMENT
İf you are going to just boss farm like meph and andy meteorb is great but in general farming too many fire immunes to kill with a crappy orb
İf you are going to do more general farming i recommend building max orb (with synergies) and firewall for cold immunes more versatile
SİNGLE ELEMENT
İf you have a sunder i definetely recommend going single element
Fire sorc
When geared it is the fastest killing sorc in the game imo but you need baseline flickering flame and enough tal pieces to get -fire res from tal orb (or a few -res fire facets)
Phoenix shield is as good as it gets 
Cold Sorc
İf you do not have enough - fire res then go cold with cold mastery until you have the gear
Blizzard is the go to option here
I’ve made Fireball/Meteor Frozen orb Sorceresses the last 3 ladders and back in D2. They do work. Use static on tough mobs and fire/cold immune bosses + TK so merc can land blows. In the early ladder I will string out mobs of fan/cursed night lords and spam glacial spike along with FO if they are FI. I use meteor to thin out large packs of non-FI monsters. You do not need to max Cold mastery, but it is worth at least 10 points depending on your play style.
Personally I think for just playing through the game Orb+Hydra, then go mono elemental after sunder works better. Skip cold immunes unless it’s a boss pack, or needed for a quest. I tend to fine on orbballers with bad gear you end up mostly using orb anyway, and Hydra is better for picking off the occasional immune with less investment.
Pure Diablo still has the OG Meteorb guide by Sasja up.
It recommends:
FO: 20
CM: 8
Meteor: 20
Fireball: 20
Fire Mastery 20 (put a few of these into fire bolt instead if you find you use fire ball more than meteor and/or have +skills)
That plus pre-reqs finishes at 90, and additional skill points are recommended Fbolt or CM.
There’s a section that maths it all out on why you what to get CM to what level, but it’s possible the info from 2005 has changed for the latest D2R patch.
Either way I feel it’s certainly still worth a read.
I’ve made a few over the years, I feel like fire ball + meteor get you through normal well, then FO obliterates all of NM, and then by Hell you have both well leveled so you can take on CI and FI as needed.
I do agree cold is a bit less powerful in Hell (not surprising given points spread), but it still does pretty well. The timing of Meteor can be annoying, so I do find myself using Fball a lot more, but the damage of Meteor is really nice for hard targets, especially if they are pretty stationary. Using tele to place merc and then walk a few steps away to drop Meteor’s on merc’s head while he’s tanking enemies, and throwing Fball in while Meteor is on cool-down works pretty well. With the new quick cast menu it’s really easy to see when Meteor is available again.