We also consider to use touch panel ... to eliminate number of buttons.
Please carefully ask and listen to customers, who are using the device for training and competitions
and not just as gimmick, if they really want a touch screen ! I'm sure, you'll find both meanings.
I personally prefer buttons ! Even on my smart mobile phone, I sometimes wish that I had my old buttons back.
But using a device during training or competition is different. I need a very clear button press for
switching a display or ending a lap. I don't want to verify two or three times, if my screen touch was
successful or not.
And I think, there are only two possibilities: Either you have small (virtuell) buttons on the screen, which
have to be touched. Those a very hard to aim during an outdoor activity.
Or (second) you have to wipe through a large number of displays to find the right one. Both I don't like.
Furthermore a touch screen could be effected by water (rain and sweat), by clothes and gloves.
If you ask me: No touch screen. This is for sitting in a pub and showing a "cool" device. Not for outdoor training.
(just my opinion !)