some people just prefer to play the game a certain way. it’s a chore sometimes to change up heroes, and even if you max out team slots, depending on how you use them, you’ll only have so many possibilities for so many different kinds of raiding teams.
my current raid defense TP is around 4k, off the top of my head. all heavily emblemed 4* heroes in a double formation. i’ve noticed that players who don’t stack colors tend to lose against it more often than players who go 3/2, 4/1, or mono, and i know why that happens.
i hate playing rainbow because it’s such a different way to play the board, and depending on cascades to be able to charge multiple heroes in time just isn’t how i want to play the game. it’s not fun to me, and it’s a dangerous way to attack a team like yours where it’s difficult to take down any one of your heroes if multiple attack heroes don’t charge at the same time.
your defense is one of the bigger “pick your poison” defenses out there. you can take out one and the rest can still pose huge problems even if you’re able to knock out two or three heroes. and even if you take out four of them, Heimdall can bring them all back–sure, it’s not likely, but it’s not impossible either.
so yes, your defense is difficult to attack, even with the right heroes and the right board–and by “the right board,” i just mean something workable, not something that works entirely in favor of the attacking player.