I have far too often run into these problems as the player with the most games played amongst my high elo dominion peers, and can accurately describe the problem with the handicaps on the Crystal Scar. There are a constant flow of problems ranging from champion imbalances and item imbalances that we are all too familiar with these days, and some people fail to recognize that the map mechanics are what facilitate the champion and item problems.
Let me explain exactly what I mean:
Your team gains a solid advantage early game by outplaying the opponent and maintain a four point capture on the enemy for ~6-7 minutes, reducing enemy nexus health to less than 50. By this point we expect your own nexus health to range between ~350-460, lets take the 350 scenario. The respawn system will trigger a 300 point difference and give the losing team a -8 second respawn timer while the winning team is handicapped by an added 8 seconds on their death timers. For some reason the post a while back about the respawn mechanics (http://na.leagueoflegends.com/board/...php?p=16196495) stated that the death timer handicap would not exceed (-4/+4) for either teams past 100 points difference in nexus HP but this is clearly inaccurate as the scenario I've just mentioned is a common occurrence and seeing 14-16 second death timers are very common in my games. The base death times are set at 26 seconds, I regularly witness death times of 14-16 seconds. The handicap is extending beyond every hundred health difference between Nexus'. The respawn window starts when a player dies and lasts twelve seconds. This means that if the winning team has a significant advantage of 300-400 difference in Nexus health, the losing team not only has a 16-20 second difference in respawn timers, but it is quite possible after an ace for 4 team members to ride a wave respawn of ~3-5 seconds. Now what about the respawn window of the winning team. It is only increased by half the added respawn timers. for a 300 health difference (-8/+8) the winning team's window becomes 12+(+8)/2 = 16s.
Now let me explain the flaw in the Nexus health mechanics very briefly, it takes 2 damage from every death on the team until 100 Nexus health. This is a huge problem when accompanied by the respawn timers/windows. Even if you are constantly killing the enemy team because their death timers are low enough to meet you at the Windmill almost immediately after the fight they will not lose Nexus health.
To put it simply, when you are up significantly in Nexus difference you have no means of reducing the enemy Nexus health. You cannot capture three points because of respawn windows and timers, and no matter how many times you kill them, you cannot reduce the enemy's Nexus health after it is at or below 100 points.
If you would like a clear example of how this encourages poor play, please scroll to (3:52:00) of this DominateDominion #39 tournament Finals game NMUH vs PECS Game #2 found here (http://www.twitch.tv/dominatedominion/b/356492515). NMUH clearly has control of the game and outplays PECS for the entirety. The problem starts after getting the enemy nexus health to below 50. Even at this point NMUH is wiping the floor with PECS in terms of kills, farm, and gold. But PECS is able to respawn to defend points even after being outplayed and killed after riding a wave respawn together only a few times. NMUH has no way to reduce the enemy's Nexus HP and PECS builds momentum with far lower respawn timers. The momentum allows them to kill the winning team once or twice and with NMUH dead for ~30 seconds per death this allows for a ridiculous amount of comeback potential when the winning team cannot wave respawn to counter.
I propose other methods of being able to reduce enemy nexus health or to actually fix the maximum respawn timer difference to accurately represent a (-4/+4) seconds.