This seems more of an opinion rather than a suggestion…
In short, you want a map that is as easy and as enjoyable as Cryptic Castle right?
There are maps that I can say which is not that easy however enjoyable. Like Laboratory of Madness and Pirates Harbour, and I’ve gotten past Round 20 on those maps. You do need a little bit of hardwork to get past round 16.
There is a post here somewhere in the forums that provides strategy for each map, search for it that might be of use to you.
There already are NEW maps which I find easy and enjoyable. Like the new map “Snow Ruins”.
To play it just type /vote Snow Ruins in the Intermission. Its pretty easy