Okey, from the Information you Provided, I can tell that you appear to have no Idea what you do.
I was under the Impression you did at least take a Look the Instructions on "How to Beginn" in the Wiki.
So I´ll start at the Start:
This Wiki is your Friend.
The Most Important thing ro remember when you Tinker with TerrainControl is:
Changes you make to the Config files dont change Chunks already Generated.
The Jumbled Mess you got, (if you didn´t change anything else, and everything is freshly generated from TerrainControl) results from this. You have Chunks with the settings of the Default Ocean, and Chunks with the New Water Height.
To not get this Issue, remove your World/Region Files everytime you change settings.
I cant see any Biomes from the Screenshot. What A Biome Looks, and what it Actually is, can be Quite different.
Use /tc biome to actually KNOW what Biome it is Supposed to be.
Still to Check how Much Land is beeing Generated, make /tc map and take a Look at the Image it Generates.
And Maybe Provide this Image, because thats the Issue you had.