It’s cookie cutter because a rare Ammy that’s actually good is harder to come by. 20fcr better than 10fcr crafted sure, cause you’re just getting 1 more stat unlike rare where you get 2 extra. You’re not dropping any unique ring, you’re adding one and using arach.
its cookie cutter because 2/20 is signficantly better than 2/10
By using 2/10, you are gaining essentially 2 affixes over 2/20 but for those 2 affixes you are having to drop a unique ring, wisp in particular, which grants a 40% reduction in lightning damage taken + gives you an additional meat shield through oak.
There are no 2 affixes that ever give you that level of value.
a plain 2/20 > this ammy. Its not even close.