I think you hit the nail on the head with the same defense thing. I run 2 2 1 rainbow and 2 1 1 1 but lately I feel the aggravation always facing the same teams. It literally comes down to decent board or not or how high there troops are. This is overly significant in diamond. When I worked my way through gold and platinum there were so many different teams but when I got to diamond is just way to many same defenses.
Another issue I think ties with this is that raiding is really the only place to use your mana controllers and certain heroes specials never get to shine because none of the maps on season 2 have any boards with mana heroes until the end which means you rarely get to practice anything exciting as you always countering the same heroes. I feel that if there were mana heroe board like season one people could defnitely try out way more builds instead of finally leveling someone up enough to hope they do well on a backup war team.
I tried mono but it was like have 5 wu kongs to me I just cant limit my board that much and call it enjoyable.
Diversity i feel is the bighestbissie and why raids are getting stale. Way to many heroes are never even seen on defense teams anymore