Just food for thought talking strictly about caster dc and not talking about filigrees.
We had +20 cha, +9 insight cha and +4 insight cha. Now we go up to 22, 10 and 5. Sounds great (4 cha benefit = 2 dc), but in reality it isn't. Slavers set gives 4 cha and FOUR dc. The various sharn dc sets give 4 cha 3 dc, (or 3 cha 4 dc). So really we could just keep all our slavers gear and simply swap to the +22 cha artifact necklace and end up with pretty much the same dc as regearing completely. That's anti climactic with all this new gear.
You have raised dc's in sharn by a lot.
My suggestion is that you increase ALL 4 of the caster set bonuses to +4 stat (cha/int/wis or whatever you have now) and +4 dc to at least match the slavers set , which is now 2 expansions old.