Any collection of squiggles can qualify as plausible. For example, if I want a triangle that spans most of the distance from equator to pole with a hook at the bottom and a teapot spout at the top, that's perfectly plausible. If I want a large sea completely surrounded by land so that it looks like a mutant duck, that's also plausible. If I want a ring of islands with a big dome of ice occupying the space between the islands, that also is plausible. In fact, if those things were to occur here on Earth, we'd probably give them silly names like South America, the Mediterranean Sea, and Greenland (that last one because it's almost entirely covered by ice - that's just how humans work).
How you fill in those squiggles with mountains, rivers, and biomes will have a much bigger impact on plausibility than the raw shapes. Any underlying physics adjustments and the history of how the squiggles got there would also play a huge role in plausibility because they could potentially play a huge role in the aforementioned locations of mountains, rivers, and biomes.
If you're asking "are these squiggles pretty?" then that's a completely different question, and it's not one that I'm particularly well-equipped to answer. Do they meet your needs for the stories that you want to tell? Only you can answer that one.
About the only advice I can give you will probably be less useful than you might hope: it's much simpler to start from a set of tectonic maps that represent the time history of the planet and then generate the topography than it is to start from some squiggles and try to retrofit your desired state from that.
The less-helpful part of my brain needs to ask one question: do you truly need a whole-world map for the stories you want to tell, or would a rough map with simple symbols serve your purposes equally well?