Ice blast will increase you 4,8k damage per blast if you go from lvl 1 to lvl 15 with 100% attributes and rune of ice. I’m personally doing 30k per ice blast, having 4,8k more per blast would be ok, but, not worth investing 14 points of other op cryo skills.
@Indygo PP + Ice wall doesn’t do great damage? sorry to interrupt but i do 30 Milion, on 5k MATK only (there’s ppl already rolling 14k with chapparitions). Ice Wall + PP is great because of it’s scaling, every bit of damage you get becomes a lot more in scale. OFC a full con build without great investment is never gonna do damage.
For rank7 alternatively you could go Warlock: 1 good damage, 2nd Mastema synergy with new rune of justice (mastema increases damage taken by holy property and new rune of justice is gonna be 2 overheat and holy property), but yet again, you are not wiz3, and having a 6 second csat rune of justice is shitty.
AS far as i know , cloned ice walls don’t shoot shards, but can be ice blastes.
Ice blast has 1 aoe attack ratio, taht’s true, and linker would make you hit all targets with ice blast, but you are not gonna do marvelous damage without nice MATK. AS i said, i have 3k MATK, with lvl 18 ice wall (ice wall gem) on a single target i can do around 400k. With rune of ice + chapparition around 1,6 Milion damage, reaching 5k with chapparition. With linker 1 you are only gonna hit 5 targets, with a 1 min combo which won’t kill rank8 mobs by itself. I don’t knw your MATK thought,
DPS (try to save you) builds:
If you wanna cast runes you may as well consider going wiz3.
The ez DPS oriented safest route i think you could get is Warlock + Sage or either FF2 since you are full con and thankfully FF2 has hp scaling skill.
Still the warlock rune caster combo with a slow rune of justice is kinda questionable because of the lack of quick cast.
You skill points should be 10 subzero, 5 tree 5 snow 15 ice wall then 1 pointer ice blast, and share the otehrs between ice bolt and pike. Pike doesn’t even scale that well with skill level.
The other route is going supportish as everyone said, linker sage would be the easiest for you and makes most sense. CC from cryo, link and hangman, and missile hole.
Thaumaturge is out of the question, thaumas are worth if you are full int, not really for full con.