Being a child of the 90's and a massive Chikara fan, I'd be a liar if I said I didn't enjoy a good invasion angle. Sadly, in mainstream wrestling they're rarely done well. Chikara's lore is almost entirely based around invasion though. BDK, GEKIDO, The Flood/Titor Corp (which actually won and closed down the company for awhile and even 'killed off' a few roster members), the demonic and symbiotic plague of Nazmaldun (which still plagues members of the roster), and even now the invasion from within with the Crucible. Then of course you have nWo, D-X, Bullet Club, etc.
Also, as someone who watched and DVR'd old AWA reruns on ESPN, along with again being a fan of Chikara, and even as someone who showed initial interest in Rikishi's failed(?) federation Territory League, I like the idea of a Team Challenge Series which essentially consists of making teams (occasionally ones who specialize or represent a division) and have them round robin for some sort of prize in the long term. The only sad thing is that such a simple concept has never been executed well or flat out failed for one reason or another (In AWA's case it was departures of talents and a finale that didn't make air until it landed a reputation as one of the worst things done in wrestling in the WWE Network Hidden Gems section for awhile, in Territory League's case it just kind of petered out with the company, and in Chikara's case, despite how in the numbers they are about everything else, their finals didn't add up nor did they really keep tabs on win-loss records it seemed). I'd love to see New Japan or Dragon Gate take a swing at it.
My least favorite might be the manager with a cadre of jobber to the stars types vs babyface face of the company. It was a common trope with Hogan and only really worked once with Heenan in the 80's when Brain actually brought a few accomplished heavy hitters into his Family. Even the ones that weren't up to snuff at least had the rub of having a manager to the stars like Heenan in their corner. The only problem with this angle is that there's no suitable payoff or end game. What's Hogan going to do? beat up Heenan? Put him in a Weasel suit? seems like bullying and not very babyface to me. The worst was obviously the Dungeon of Doom, which had zero credibility and was chocked full of midcarders at best and a reluctant Lex Luger who wouldn't go along with the camp 60's Batman villain look.
I hate love triangles as well. They had some good ones back in the day, but the last one that was probably worth anything was Christian/Trish/Jericho. Matt/Edge/Lita had plenty of heat behind it, but the payoff was Edge going over, so yeah...70's and 80's wrestling did it well though. Even ECW aping Memphis did it well with Dreamer, Raven, and Beulah. Meanwhile, how many have Lana and Rusev been in now? and how many have ended well? or at all?