I bet bash builds get more kills than dex one. I've never tried to say overwise. But usually there are a lot of factors that you have to take into account before you use any statistic. I can tell you as person who finished best math university in russia

Like:
1. How many expirienced warrior players did play dex build.
2. How much hours did they play dex builds compare to their successful bash builds.
3. How many hours we had bash builds(3-4 years?) compared to how many
hours dex builds become popular(1 year?)

Obviously, you can not just take numbers without taking into account at least those three factors if you want to prove anything.

Also thing is that dex builds(I'm speaking only about elves with striking) has better options against almost all other class. For example:

1. As dex build you don't have to worry about bard as giants have.
2. You don't have to worry about transmuters with neor as giants have.
3. Same goes to necros/ap with sleep
4. Invokers can not abuse your vuln.
5. You don't have to worry about warrior with bash. while bash build has to. unless you have greetings.

And so on.

And so on. Giants only better against assassins(assassinate only) and thiefs(bj, steal) mostly.

It's like bards, you can make run a lot of people with an easy but it's not easy to seal the kill, while with bash it's simple.

btw! Do elves with striking bash better than elves without it? From my expirience it is so. But probably it was leader bonuses or rng.