But what users need to do in return has become gro...

有的，这句话现在是 不通顺的。问题主要在这一段：

has become grown far more complex

has become 和 grown 不能这样连用，相当于用了两个表示“变化”的动词，语法上冲突。

你可以改成下面几种都正确、自然的说法：

1. But what users need to do in return has grown far more complex.
2. But what users need to do in return has become far more complex.
   3.（更口语一点）But what users need to do in return has gotten far more complex.

整体结构 “what users need to do in return” 做主语是没问题的，in return 放在这里也可以，表示“作为回报 / 作为交换”他们需要做的事情。

所以只要把 has become grown 换成 has grown 或 has become 就可以啦。