Thanks to all of you, in the end i've decided to go with the rogue route to don't argue with my GM, the pg is gonna be pp as fuck anyway so better not leave anything in his hands for interpretation.
The full progression is gonna be:
Domain Elf Combat Wizard 1
Domain Elf Combat Wizard 2
Domain Elf Combat Wizard 3
Domain Elf Combat Wizard 4
Domain Elf Combat Wizard 5
Unseen Seer 1
Unseen Seer 2
Spellguard of Silverymoon 1
Spellguard of Silverymoon 2
Spellguard of Silverymoon 3
Spellguard of Silverymoon 4
Spellguard of Silverymoon 5
Olin Gisir 1
Paragnostic Apostle 1
Paragnostic Apostle 2
Mother Cyst, Precise Shot, Collegiate Wizard,Point Blank Shot
Iron Will (Otyugh Hole Complete Scoundrel p.151)
Arcane Disciple(Competition), Spontaneous Divination (Variant)
Feats gained with chaos shuffle by trading the 4 elves weapon feats: Dragontouched, Split Ray, Practical Metamagic (Maximize Spell), Arcane Thesis (Shivering Touch)
Spell Mastery, Random Bonus Metamagic Feat->(chaos shuffle :Singature Spell Shivering Touch)
So basically i'm gonna make a sneaky gish that can cast as a swift actrion a maximized, reach and splitted shivering touch for -36dex and then make a full attack with a composite longbow with persisted Hunter's eye, greater blink (to secure the sneak attack), divine power, wraithstrike, bite of the werebear, arcane spellsurge (with the mobile spellcasting combo to switch casting time to standard if needed) and ANTIMAGIC FIELD thanks to spellguard of silverymoon selective spell ability.
I'hope my DM won't regret saying to all of us "do your best to impress me" and i hope he's gonna be up to the task since the other players are gonna play broken characters too, i only know one is gonna be the cheater of mystra. I wouldn't know as a DM myself where to start to master this kind of PP characters especially since we are starting at lvl15 so with an almost fully functional build.
That being said got any suggestions to improve it more?