If one has played enough CC, they will have noticed that people who are in the deep end of playing ranked CC (which to keep things civil I will just say that I have no interest in Ranked until PvP is overhauled) sometimes decide to go and punch down on people that just want to play casual, effectively raiding the casual queues and ruining it for those who just want to do a 5v5, maybe win, maybe lose, have some fun, earn some tomes.
A fair solution to help combat powergaming in casual CC would be that, when your team has the crystal in the enemy's checkpoint or beyond, your teams back-third of the whole field becomes some kind of poison zone for enemies, inflicting significant damage (5k damage per second regardless of shields) to any enemies that enter and remain in it. That may sound odd, but the point is that there shouldn't be any in it- the issue is that only overinvested powergamers from ranked, who do not belong in casual, would chase or hunt all the way into your teams backfield at this time, to get a kill while their team is fighting on the crystal on the opposite side. The poison zone at your base's end would disable if/when the crystal gets pushed back through the enemy checkpoint towards the middle and your teams base direction). The ranked-players-raiding-casual element that makes the experience unfun wasn't something you saw on day 1, but it's quite common now. Please recalibrate casual CC for casuals with this fix. No genuine casual players will be negatively impacted by this.
Where the 'poison' zones would reach when you have pushed the crystal into the enemy checkpoint or beyond:
Palaistra- From your base to the bottom of the stairs that touch the middle area. (and horizontally across the map either side, partially covering the speed zone yes).
Volcanic Heart- From your base to the top of the stairs that touch the middle area (and horizontally across the map either side, again covering some of the speed zone).
Cloud Nine- From your base to the bottom of both sets of steps that touch the middle area.
The Clockwork Castletown- Pretty much from your base up to the portal door ahead, and from here horizontally across 4 of the 5 flipboard zones and covering the checkpoint side.