I feel caves are a bit scarce.

I haven't found myself exploring caves too much. They feel fairly empty right now. On the surface, an applicable amount of ore spawns, so I don't really need to go underground to get ore.
Right now, as well, there are very few chasms, caves are very shallow, I've found only a few caves that actually act as anything more than just a hole.

 

try going down in a cave to the lowest point and then just dig down further (dont forget a way to get back up). it wont be long before you hit the next cave.

i do think it would be nice if caves could link a bit beter then they do.

 

Yeah i hit the lava , crazy ores down there

 

And most of the underground caves are too small and disconnected from one to another so you have to dig most of the time rather than discovering new cave by exploring, but I must disagree about the ore spawn as there are more ores deep underground especially iron compare to the one on the surface.