The relics encourage snowballing like crazy, it's definitely possible to make a comeback victory, but it's much, much harder than it should be after a team gains even a small advantage.
The fact that the relics provide a percentage-based bonus rather than a flat amount based on your current level or length of the game is a problem too. If one team has a sizable gold advantage over the other, and the losing team manages to win a teamfight and they take control of both relics, it's going to be far less of an advantage for them than it is for the other team, because they don't have as much AD or AP to boost with the 10% bonus, even though they have to work so hard to get control back.
Then again, even if it was a flat bonus, there's still much easier and more of an incentive for the winning team to hold control over both relics, so I guess it doesn't matter too much. Maybe the point of the new TT is to let one team snowball and end the game fast? If it is, then the relics are fine, but if they're looking to create a balanced map that might see play in tournaments, then they definitely need to change them.