Just to chip my

...
My own denomination does adhere to the 1646 WCF. It does have a Scottish connection and John Murray is acknowledged to be the founder of our denomination.
I believe the 1646 WCF to be the finest systematic expression of Biblical theology in credal form yet developed. It is a confession of what the Bible teaches, based completely upon Scripture, with the purpose in mind of uniting the church around those things which must be believed.
Not every point of doctrine contained therein is essential to the faith, but it is all true and, as I said, based solidly upon the Scriptures.
The WCF, like most or all Reformation creeds, upholds the truth that creeds are subordinate to the Scriptures. But they summarize very nicely what the Scriptures teach.
As has been noted, doctrines like the Trinity can be proved from Scripture and are cardinal doctrines, but the Confession articulates the doctrine very succintly and faithfully according to the sense of Scripture.
Although every Christian should be grounded in the Scriptures above all, for they are the word of life, the Confession and Catechisms teach us what we need to know. They help us to confess and understand what we believe the Bible is saying.
I have no problem quoting the Confession in a thread on the Puritan Board. The Scripture proof texts are available for all to read. Sometimes I include them and sometimes I don't.
I liken the Confession to Nehemiah 8.8: So they read in the book in the law of God distinctly, and gave the sense, and caused them to understand the reading.
I too do not think it necessary for the Church to reinvent the wheel when it comes to summarizing what we believe. On the contrary, I fervently pray that we might return to our Confessional heritage. Let us stand upon the Word of God, as understood and taught by our Confession, and upon the shoulders of those giants who have gone before us in the faith, and may our conversation be thus framed aright. May each generation affirm the orthodoxy of the past (own it as our own) and if possible build on it rather than returning to square one.