I figured another board change might be more useful than another orbchange on a team that cares about high combos, since it sets up a board that's probably well-suited to a bunch of individual red combos. And my sense of symmetry is more willing to accept that leilan is less "strictly worse" than Leilan compared to cao cao vs. Cao Cao since he only gains one enhance and she gains two. But that's just me being dumb, you're probably right. And that delay will definitely be handy.
So on a related note, the one major type of team I don't really have any experience playing is combo counters. I've got a row team, a prong team, a rainbow team, a stall team, but no combo team. Krishna seems like he's sort of that, which is cool, because it will give me a chance to practice my combos and get better at the game overall. But since I just pulled Kushinada, is there any merit at all to running her as a lead? She seems like she's just way less efficient than pretty much any other combo lead, and her awakenings don't really work toward that end. Am I overlooking something about her leader skill that makes it less crappy than I think it is? And don't say Weekend Dungeon, pretty much anything can clear that even with a Ganesha friend so I don't need a lead just for that.
Well, don't forget that boardchanges aren't always reliable. You can pop Urd or leilan and get very few fire orbs-- don't forget that to get Krishna's full multiplier, you need to match at least 11 orbs-- five connected fire orbs with at least one enhance and two more fire combos to get the maximum 45.5625x multiplier. So it'd be a waste of an active if it doesn't give you at least that many!
cao cao is a failsafe, instead. He can work on his own-- and if you don't get enough fire orbs by using him, you can use the delay to your advantage and try to skyfall more, which will likely solve that problem-- or you could pop him with Urd for a maximum power attack or fix her boardchange if she doesn't give enough orbs. The purpose of the board changer here is less for the orbs they give and more to clear out unwanted orbs on the board, especially poison or jammers. The biggest flaw of the team at hand I feel is that your RCV will be pretty mediocre thanks to having only one heartmaker on board and having two units with <100 RCV (cao cao and Kagutsuchi)-- so being able to make sure as little as possible gets in your way is best. There's good synergy here-- both cao cao and Kagutsuchi can work with Urd's board and have good additional functions to their actives. leilan does not-- there's nothing on your team that can work with light or wood-- in fact, there's no light or wood on your team at all. So those are worthless to you.
And if that wasn't enough, cao cao has much higher HP and almost double the ATK leilan has, so he'll hit much harder and serve as a bulkier sub. All of this is far more valuable than the one extra 5% boost that leilan can give.
As far as Kushi goes, I feel her value as a leader has kind of diminished. She's fantastic and has an enormous multiplier potential, but even at 10 combo you'll only be doing 25x damage, which is pretty difficult to get as it is, and there are so many better ways to get that kind of multiplier. She definitely does shine on tricolor dungeons, but not so much elsewhere.
She's far better as a sub. A nice, fast, massive damage reduction, a skill bind resist, a bind clear, and a time extend are all pretty nice. But as a leader? Unless you build your team to be able have lots of time extends or board control to reach high combos (like
this), she's just not worth it, I feel.