I think that they should add grass that is illegal to trade but can be placed so you can build stuff using grass because using real grass blocks cost so much
Terraforming will always be a costy activity. Use green clay if you're really struggling. I'm not entirely sure how a different illegal-to-trade grass block would even work... If people weren't regularly terraforming and turning grass into dirt, the price of grass would slowly become less and less. the great thing about using grass as a currency is that it stays a consistent price - the grass to diamonds 2 years ago was 25 -1, now it's about 22-1. It's hardly changed, which is exactly what you want, really. It means old players can return and not be broke/rich all of a sudden. Grass must become dirt. No support.
I have no idea how this would work and how it would be possible. I do see where you're coming from, but I'm gonna have to say no support. Lycel also stated some more reasons I would say.
Honestly, dirt forms into grass after awhile. Also, How could you tell the difference between normal grass blocks and building grass blocks? This could increase the rate of scams: Players show the Build grass blocks like trade grass blocks but give the player the build grass blocks, ending up as a scam. I'm very sorry, but unfortunately, no support.
...No? Definitely not. in 2015, it was about 23-24, in 2014, it was about 25. I wasn't here before that, but I was talking about 2 years ago specifically.
No support, I'm not entirely sure how you could have illegal to trade grass which differs from normal grass. As with many above, I agree with Lycel.