You can always add more Vita of course, Kitteh. That does quite a lot on a Barb with a decent BO level. You can pretty much choose how fragile you want your Berserker to be with the Strength vs Vita tradeoff, but of course a less fragile Barb will also do less damage.
And yeah time traveling is definitely not a requirement for a Berserker. Daz is using the standard 1.13 setup that's totally fine and very strong (Cham Shako, 2/FCR/MF amulet, Enigma, Grief, 6Ist PB, Nagelring, Nagelring, Chance Guards, Goldwrap, War Traveler, 90-100 FCR on switch (some combination of hoto/wizardspike/suicide branch, enough to get to 105 with the FCR from the amulet)).
The only normal time travel change would be to Cham a 1.07 Shako instead. The other time travel stuff I have is pretty unrealistic.