Sorry, nothing you are saying here makes any sense at all. This isn't a matter of personal preference or trade-offs. Dex would be superior to int builds and it's not really close. Int helps in little things that don't really matter such as lowering 2 skills a little so you go from "no-fail" to "no fail". Giving a little more damage on kta.
Turbine really has 2 choices here:
1) Keep assassin tree as int-only
2) Make assassinate better of dex or int and give a few easy buffs to int-based assassins so both are viable
I think the 2nd choice is best so people have more options, but the first option is better than adding dex to assassinate and calling it a day.