Frozen Orb is not viable as a main skill anymore, that's why your Sorceress isn't any good at MF now. The reason is that Frozen Orb doesn't have any synergies. You really need to go for either Meteor, Blizzard or a combination of Lightning and Chain Lightning. If you use Meteor or Lightning skills, Frozen Orb makes a good cheap secondary skill to take out Fire/Lightning immunes.
What? cold spike is a synergy to FO and I know, my sorc is a cold/lightning hybrid with only 1-1.5k lightning dmg and I can still solo hell fast. ;D
I used to do hell andy, meph and dia for fast mf runs but since I wanted to gain more dmg for pvp, I had to give up some mf items. Can't do the pit since my lightning is too weak to kill fast enough (and they are cold immunes), the mob's in there are fast and hard. :d
FO can be decent with good gear (which I got ;o) but it's hard to play if you can't get the dmg, life/mana, speed and res. (lol, I remember in the old days when my lev 80 sorc had around 400 orb dmg xd)
So I forgot Ice Bolt (not Cold Spike) synergises with Frozen Orb, but it's a pitiful 2% damage per level. Skills like Blizzard not only do more base damage than Frozen Orb but also have 3 synergies which provide 5% more damage each per level instead of just 2% per level of a single skill.
My magic-find sorceress doesn't have good gear, not even a single cold facet, but she has a henchman to tank the enemies while she casts her 3300-3500 damage per second Blizzard. It's strong enough to take out Hell Mephisto from full life in about 5-8 seconds, but with Frozen Orb damages ranging from 300-400 damage per shard you have to run in there and Static Field him down to 50% life then try to get your FO to explode right on his body to do maximum damage. It takes much longer and is harder to do.
Every magic-find Sorceress I've ever created in the past has been a Frozen Orb sorceress, this is my first Blizzard Sorceress and she's much more powerful than any of my previous ones, hands down.
Yea ice bolt (lol, I forgot it's name, making a new cs zon in ladder so haven't played my sorc for a while).
The only downside I see on blizz is that you have to spend quite a bunch of skills on the other synergies to get it strong, I'd rather put those skills on ES + warmth so you can survive better and/or to a 2nd element to get rid of those immunes (pvm). Also in pvp blizz doesn't always hit, if the opponent is fast/tele's around and staying under a blizz doesn't always work, not everyone needs to get close to you and the pure vita build's with cta's and oak's (around 7-8k life) can take a while (ok, really good blizz sorcs can 1 hit everyone though [except absorbers, damn lamers]). :P
I used to have 400-500 FO dmg too, now I got almost 1.1k dmg (hell meph doesn't take long, 2-4 orbs if I get them explode on him) and I got 2-3k blizz right now, can raise it more by merely changing my belt to snowclash but yeah, I had to give up on most of my mf items to get items that boosts up my dmg. Sure with the items I got, I'd probably do waaay higher dmg with blizzard than FO but the current dmg I got is enough to ensure me win's over most duels, killing all hell bosses in a decent speed AND the skills that I didn't have to put on all the synergies allowed me to gain high mana reg and decent lightning so I can solo hell. ;O
FO can be good, it's just expensive to get it good.
Oh yeah, the dmg's per ice bolt.. FO shoots quite a bumch of them too, you just need to aim it well. ;)