Thanks haha. I’ve thought about making melds clearable in more formations but honestly I like the more restrictive and challenging way it is right now (with melds being more visually simple too). Considering you only need to clear 5 things per round, I think the tradeoff of those clears being harder to achieve is fair.
The straight-line melds combined with your straight-line pieces means you can get screwed over by drawing a tile in the wrong spot (similar kind of feeling as in regular mahjong when you get screwed over by drawing something that would’ve worked with something you just discarded), like having something in the outer columns that your middle tile can’t get to.
Your dropped pieces having two outer tiles and one inner tile means it’s less likely for the tile you need to be in the middle, which is something you can take into account when filling up the board, but that’s a risk you have to take, as that can still go wrong a third of the time! It’s that nagging feeling of failed setups being your own fault that I love to see happen when I’m playing it myself too.
And yes, kokushi and chiitoi have to be built as 14-tall columns :) They’re just as risky, inflexible and hard to change course from as in regular mahjong. Also, the tiles in those hands have to be fully closed and you get locked out of it if you clear any melds that round!