Overall, I'd say that I rather like this game mode....but only for a few rounds. I'd like to do endurance runs on this game mode, but after only a handful of rounds in, it becomes really annoying and frustrating. There are a few reasons why it gets to this point so quickly.
The first are all the nullifiers. There are just way to many as time goes on. There are the regular nullifiers that walk up to you, as they are melee... then the demolysts that have that pulse nullifying bubble thing... I get that we're very powerful and strong and need some way to counter that, but I don't think throwing so many nullifiers at us, that it basically just turns off all of our abilities for the rest of the mission, is the way to do that. Wisp is my new favorite frame and I love to take her into this game mode, but it gets to the point where trying to use her pods is just a waste of time and just gets you killed. The second you cast it, there's a nullifier to just take it away instantly.
Secondly, The demolysts are soooo tanky. I just sit there and unload my rubico prime into them and barely make a dent. How can my rubico take an eidolon joint down faster than these things??? So I feel there needs to be some improvement on that mechanic in some way. You can keep them tanky, but maybe don't have them run so quickly to the defense objective. Or maybe have them way pointed as soon as they spawn so we don't have to run around trying to listen for them, only to find them when there pretty much at the defense objective. Also, if you get an enemy buff modifier, you basically just sit back and let it destroy the objective... cuz no way you're gonna kill it before it destroys it.
Finally, I can't go without mentioning the rewards. Much like a lot of other content, the replay-ability is very limited. You get the mods, and then move on. Even if the relic rewards were radiant, not sure I would still farm it for the relics. I know this is a well known issue throughout the game, so I'm not gonna ramble on about this.
But like I said before, I generally love the concept and flow of the new game mode. I'd really like to spend more time playing it, but it just gets annoying too quickly. Hopefully we see some changes in the near future so I can spend many hours in this game mode with the beautifully remastered tiles!! Nicely done on that DE.