Judging from the field and town at A1 on ndisles, both still fit within a terrain cell, and clearly htc has the ability to run a search and replace on the current TE names. So if you're building an MA terrain, Skuzzy can upgrade it if you submit it, and you can upgrade it if a TE update comes out before you finish it. Either way, there's no reason to stop work on it. If it contains custom shapes and objects, a new TE won't matter unless you want the new htc buildings and textures.