Well, if you stick to Ascended, your damage loss won't be 10%. Berserker and Marauder are much closer than that in terms of damage. Assuming Scholar runes, Truffle Steak, Superior Sharpening Stone, and a Berserker weapon:
You also have to take crit chance and crit damage into account. Marauder gives you better crit chance than Berserker and only a slightly reduced crit damage modifier. When you run the numbers for those against the different base fireball damage for those same combinations, you realize that the difference in damage is very, very small:
Stats | Crit Chance | Crit Modifier | Avg Fireball | Health --------------------- | ------------- |------------- | ---------------- Full zerk | 54.05 | 220.67 | 1988 | 11645 Marauder Armor | 56.95 | 213.47 | 1934 | 13715 (+17.7%) Marauder Trinkets | 59.52 | 210.13 | 1910 | 14725 (+16.4%) Marauder Both | 62.43 | 202.93 | 1851 | 16795 (+44.2%)