Feedback Required EXP 1.7 - New Water

I don't have a screenshot of this yet (left the area a while ago) but on the planet Mata on the official exp server you start in an underground POI. It spawns next to a shoreline, and when you go to the bottom of the POI you can see a diagonal wall of water clipping into it. I didn't understand what it was at first, but now it seems like you have to increase the buffer around water areas so that POIs don't spawn in the bounds of the underground curved edge of the water surface. Or do something different with that underground water surface.

 

It actually took me some time to actually find water on my 1.7 X test scenario, but when I did, I was suitable impressed.
Not only does the new water system LOOK exceptionally good, I was equally impressed at the way the water actually flowed through areas of modified terrain, and spent quite a bit of time carving out waterways. I've not yet tried any sub-aquatic construction, so I have to ask the question:

Has anyone tried any underwater construction, and if so, do constructs under water behave in a "water-tight" fashion? As I recall, though it has been a while, the only method previous viable for creating something under water but with an atmosphere, was to use the terrain fill function of a drill to fill the construct with dirt, then remove it to create pockets of air inside sub-aquatic structures.

If not, has any consideration been given to create "water-tightness", in a manner similar to how constructs are air-tight, or perhaps enhancing the Ventilator to purge water from submerged constructs, which would then also include HV's, SV's and CV's, as well as BA constructs, in the same way these already add "O2" "blocks"* to such constructs?

* These "blocks" would be the invisible "O2" markers we can see with the "View Oxygen" function. I suspect these could potentially be tweaked to be considered in a manner similar to how removing terrain has previously created "air pockets", though I do suspect this would take some very clever programming "trickery" to pull off, though it would also likely be very well received, not to mention opening a whole new dimension in both POI and general base construction options.

 

I do not enjoy having the water effects go deep under the group (all the way to the bottom) if you build near or IN water. I used to be able to build my base in a lake and only have to the "gravel" level actually have water in it. Now I get these funky water effects all the way down and trying to build down there and make sure your blocks are in the proper direction is difficult to impossible. Even though the old water was completely static it did not suffer from this issue and it now makes it so trying to build my greenhouses underground is far less enjoyable...