Drums: Many hymns lie outside the comfortable 4/4 time signature. Veteran drummers will probably love the change of pace, but less experienced drummers may have a hard time with the unfamiliar time signatures. I recommend they spend time listening and playing along to recordings in different time signatures until they feel very comfortable with them. Until that time, consider using hand percussion instead of a full drum set. Nothing can derail a song faster than a drummer falling out of rhythm. It will be much easier to play a shaker in 3/4 than a whole drum set, and you’d be amazed how much a well-placed shaker can add to a song.
Piano: Worship team piano players usually fall into one of two categories: the tech savvy keyboardist, and the sheet music loving traditionalist. For the former I’d recommend some simple synth pads or a Rhodes style keyboard. Long droning synth pads can add depth to simple meditative hymns and Rhodes style keyboards are great at blurring the line between modern and traditional with a very rootsy yet modern sound. For the sheet music traditionalist, don’t be afraid to add some melodic piano lines to the song, just keep them light and flowing. Nothing will bring pipe organ flashbacks faster than a dominating, homorhythmic piano melody.
Bass: The bass guitar can make or break a song without anyone realizing. For most bassists, keep the notes simple and focus on the rhythm. Stick to the roots and occasional fifths and put most of your effort in driving the dynamics of the song. A more advanced bassist with great instincts and good knowledge of theory can be the one to bring more complexity to the hymn. The bass can add in some of the chord changes you have taken out of the guitar and piano, even using the hymnal to pick out a harmony line that fits the style in which you are playing. Be very careful when doing this or you could have a muddy, dissonant mess. Only a very skilled bassist can play these parts with a subtlety that won’t make the song feel dated or messy.
Hymns can and should be a part of the modern church. But they should be so because they are good, theological rich songs, not because they are hymns. They aren’t valuable because they appeal a certain people, or because they are better than certain other music, or even because they are part of a certain tradition. They are valuable because they, along with many other forms of worship, glorify God.
In a church I used to attend there was an woman in her 70s or 80s who worshipped in the “contemporary” service, she didn’t know most of the songs, and could only sing along to a few. When someone asked her why she would go to a service like that, she told them; “I just love seeing all of these different people worshipping, and it makes me want to worship too.”
Play songs that glorify God and help others do the same. For those leading modern worship services, take the hymns and make them a part of what you already do. Make them more than just hymns, make them into worship.