A larger surface makes the game slower not quicker, as more ice needs to be covered. Players would have less time to think and have to act more quickly on smaller ice. Hits wouldn't be a problem here anyway, this isn't the NHL.
Zach only mentioned it because the Berlin-Mannheim game was played on NHL-ice, with less width and larger offensive zones, and the game supposedly was one of the best in recent DEL-history.
There won't be any changes anytime soon, so it doesn't really matter.
The game Mannheim and Buffalo wasn't a slow game, sure the smaller surface makes the game quicker. I believe that the bigger ice surface will let guys have more room to skate and that part of the game would speed up and the big injury hits wouldn't happen so frequently. The game would revolutionize, it always has.
Of course Mannheim-Buffalo wasn't slow, Buffalo is an NHL-team, it's hard to get a slow game with such a team.
The point is, Berlin-Mannheim was faster and more intense than all the other DEL-games. The smaller ice, with bigger offensive zones, leads to faster play, because you have less time to make decisions. More ice obviously leads to more room to skate, but also more room between the players, thus more time for a player to slow things down and think about what he wants to do.
Again, big hits that lead to injury wouldn't be a problem here, because teams don't play like in the NHL. The DEL has far less hitting, especially on open ice, smaller ice wouldn't change that drastically.
Both sizes have their advantages and disadvantages. Discussing it is kind of a moot point though, because there aren't going to be any changes anytime soon.