“より重要だ” literally means “more important”.
"より美しい” means “more beautiful”.
“内容よりも形式の方がより重要だ” is the same as “内容よりも形式の方が重要だ”.
(The form is more important than the content.)
In Japanese, the expression “より” in “より重要” is redundant.
If you compare “昨日よりも今日の方が暑い” and “昨日よりも今日の方がより暑い”, the former is more natural.
“より” in “より暑い” is redundant. I notice a scent of “butter” or translation style there.
This is an interesting topic.
If you say A is more important than B, you do not necessarily think that B is important.
If you say A is no more important than B, you probably think that both A and B are unimportant.
If A and B are both important and A is more important than B, you could say A is “より重要” in Japanese.