The truth is that both dressing down and dressing up are biblical, as are all styles of music. When the Lord was worshiped in the temple they used their best dress and pomp and circumstance. They also used every instrument they could get their hands on and made quite a hoopla.
But then you also find people sitting on the ground at Jesus’ feet in whatever they wore every day of the year and it didn’t matter.
A spiritually healthy church will reflect all aspects of God’s character: His high majestic holiness and His intimate ease.
As we know, Jesus had the most resistance from the religious leaders, who simply were incapable of distinguishing between their traditions and the Word of God, and were willing to murder God rather then see their traditions eroded. Every generation has them; they look back one or two generations and lament the loss of the old ways, which to them looks like the loss of piety entire, because they can’t tell wineskin from wine.
The gospel never changes but all the forms in the church do– except those that are fossilized. Traditions are good; they give our forebears a vote. Tradition is useful as a storehouse of tools from which the church draws, but not as a straitjacket which we may not toss off.
Much of this is just the old debate about what defines the church. The 2nd and 3rd generation solved the problem of instability by defining the church by the presence of the bishop, which was actually fine for a persecuted minority, but stability evolved into control. They refused to concede that God could make bishops out of stones if He wanted and that the transmission of tradition from one generation to the next is both good for stability and useless to guarantee the Presence. The truth is, the church is wherever the Spirit is, but the problem is that His forms range from wind to fire and a kaleidescope in between. Nothing you can write into a bylaw.
Because the church is defined by the presence of the Holy Spirit, and He has been known to appear in tradition and in innovation, any Christian group whose concern is to defend “tradition” is off center. Period. Even though those traditions may be good and helpful.
Similarly, any Christian group that disturbs the peace to enact the new thing is off center. Period.
If we went by my taste, we would throw out those modern, casual hymnals and do Bach and Gregorian chant in robes. But I’d hardly trouble people over it.