I wonder how possible it would be pull this off on a fairly open map, like Dustbowl. Maybe still do-able because even the open parts are within 'nade-launcher range. Still I think the preponderance of mini-gun and shotty spam might cut down on the targe & lop mayhem. I find the targe works best when used in areas that limit lateral movement. If you can't dodge then prepare for the hurt. Except for the ability to targe while carrying the intel I don't think the demo is overpowered. I think it was a powerful class to begin with and the update just made it popular. Remember the heavy update? You get 3-4 players spamming Natascha and it was painful to be a scout. Give it another month for the newness to wear off and the number of demos will return to baseline, then I don't think you'll hear the hue & cry of "DEMO is OP!" like you do today.
Oh yeah, if you're looking for a bad/unbalanced map, poke around some of the third party stuff that's out there. Good lord there's some serious dung available for download. Certain maps may favor certain classes and/or playstyles, but there isn't a truly unbalanced map on our servers.
QFT
/me runs