The issue you have here is lack of pressure on DeathMatch maps to get immediate kills. Usually brawling teams don't have that issue, because they are prepared to take alot of damage while getting the kills, cause that's what the brawling mindset is in the first place. As long as there's at least one side that tries to close distance between two teams, because their strategy includes it, the fire exchange will happen. The problem starts in the situation when you have two teams with their layouts and strategy based on passive sniping. Usually we see sniping builds working and still providing entertainment because, while passive snipe team only defends itself, there's another, much more agressive team that puts pressure and initiates fights, causes the engagements, and their actions decide on whether there will be any kills in this match or not. But the moment when both teams' ships are based on just camping in one point and hoping for good snipe, there's a problem. No team engages, not putting pressure, so both teams just camp, exchange non-lethal amount of inaccurate long-range fire and take cover in case they take more of it, repair, then come back to sniping. Did any ship lose some permahull in this game? I believe armor fell once on one mobula. Should we remove armor or permahull from the game just because it causes the ships to be able to endure enough damage to survive long range exchange? Of course not! But same goes for removing DM maps from the pool and/or getting rid of sniping guns. All teams have certain playstyles and strategies, some of them, like GwTh, can manage to use all kinds of cover on Dunes, making them almost unseen until you're in the range of their close range guns. Rydr have their agressive-sniping approach with Mobulas. There's alot of more examples I'm sure you yourself can come up with, where some team prefers fighting on one map or another, using sniping guns or not, but removing DM maps/sniping guns from the pool during competitive events is not a solution, and neither is making them CP only.
Thing is, to win a CP, you do have one thing that you need in deathmatches - pressure. You're pressured to fight for the point in the middle of the map, and you can't really go passive snipe camping on your spawn and hope for an easy win. But sadly, what CP does is it reduces your ship choices and strategy approach. We probably won't see sniping ships at all anymore, you'd probably prefer some brawling ship to contest the point, especially since there's not enough space around the point on any CP map to effectively keep your distance with it against enemy ships. Furthermore, such things as flanks and making use of the environment, using map cover, getting to know the whole map, those things won't happen. That's a big flaw of CP maps, you're only pinned down to one point at the map, you need to hold it, you need to go for it, you ignore the rest of the big map you're flying on. What's the point of getting to know the names of every single paritan building for your strategical advantages if all you'll care about from now on is The Globe on Lab?
You end up with a problem of having a CP mode, that puts the pressure to act, which you need on DM, but in form of making one point of importance, which cripples the amount of effective ship layouts to ones being useful only close to the point, and by completely ignoring the structure of the rest of the map, which takes away alot of strategical advantages for many teams that worked hard on making them work.
On the other hand you have DM, where you're not pressured to one point on the map, and your ship layouts are dependant solely on your team's playstyle, and possibly with a little bit of dependance on the map type, but, as brawling Dune Thralls already have proven many times, not significantly enough to make your builds not work on certain maps at all. You have no pressure to go straight for one point on the map, giving you freedom of choice for approach and making use of the map's structure. Basically, no pressure at all, which sounds great, until you have no pressure to actually engage the enemy.
That's where the problem is, you either end up with interesting, intense and complex fights, with an occasional situation when no team feels pressured enough and confident with their builds to get any kills, or you get a game that will end at some point, will end quickly, and you'll have significant fire exchange, but for the price of giving away many essential aspects of competitive games, dumbing down the fights to simple "rush in for the point, kill people fast and cap", and you'll reduce the amount of effective layouts to mostly brawling ships. What you need to come up with is a good ruleset (for either tournament or the map) that will put pressure on people to actually kill eachother, or, in CP case, something that will make use of larger part of the map, so hiding between buildings, behind cover etc. would have any point on it, and also something that would allow you to use sniping ships effectively, simply put, we need kill pressure on DM, and playstyle variety on CPs.
As it has been mentioned before, I'd love to see Labyrinth as an additional map to be put in the map pool, under specific rules designed for CP maps to cope with DM ones. I also don't mind seeing some kind of mini tournament, something similar to SCS, that is only oriented around CP. But for a bigger scale, to exclude DeathMatches in every single competitive event that we'll end up with from now on? That I'll never agree on. A misread strategy for two teams during one competitive DeathMatch is not enough of a reason for me to give up all the fun that DM fights provide, just carpe diem next time and our problem is solved there. I thought that neither team would like the idea of ending up with no kills and no win at the end of the day, especially since, as you put it yourself, neither casters, nor audience, nor players themselves enjoyed ending up in such situation.