So one dip in rogue is recomended for everybody?
Vivisecionist over Rogue.
Rogue does provide free Weapon Finesse though, it can be in some cases preferable to Mutagen.
I can see that, and I do agree with you to a large extent. I am just not convinced that a Dex build is not a trap unless you are building a ranged physical attacker (e.g., archer). Strength automatically gives a bonus to-hit and to damage plus carrying capacity. Dex, on the other hand, requires one more feat to just match what Strength does.
You can also do a Knife Master 1, Wiz 3, A. Trickster X. I just dumped strength since most damage is going to come from spells and sneak attack anyway, the 8 sided sneak dices overcome my puny strength damage modifier by the mid levels, as an arcane trickster I don't care for 1 alchemist spell slot for shield / true strike and oh yes, I forget bow, two handed weapons ofc to trigger sneak attack as much as possible while spells are used mostly for disables and self protection in the front lines, you are pretty sustainable with mage armor and shield pretty early, and later you are just untouchable as long as you maintain your prots up, and of course you can always open a fight with nice AOE SA. This build requires DEX and INT, there's no room for strength no matter how nice it would be, not enough points.
For this case I think Rogue Knife Master >>> Vivisectionst.