Ocean Paradise sounds OK to me, not especially powerful but not totally useless: losing your guaranteed habitables is a downside, certainly, but it's mild compared to losing your guaranteed habitables *and* having a cursed climate preference on your main species, like what happens with Life-Seeded and Shattered Ring. Also you start inside a nebula, which is pretty cool. You will eventually find more wet worlds to colonize. The planetary modifier could do with a buff (Colonial Spirit is indeed quite a bit better overall, which is weird) but I think the overall concept is fine.
On the wider point that "tall is bad", I agree (with the partial exception of Rogue Servitors), but I don't think banishing homeworld-focused origins from the game would solve anything there.
The Aquatic trait on the other hand, I find a little disappointing to be honest. It's not bad but I don't think it's especially worth hyping either.
- The production bonus on energy/minerals/food is nice if you actually use it, but having such a trait on your primary species is situational, given you'll often have slaves, robots or a secondary species to do menial jobs; contrast with, say, +5% specialist output, which will pretty much always be useful.
- Habitability bonus on your favourite biome is good on the guaranteed habitables (if you have any!) but starts to feels like overkill soon after, unless you also take Nonadaptive or something.
- The housing bonus could be good if stacked with other modifiers, but honestly I don't find lack of housing space to be a real issue outside of Habitats (where Aquatic doesn't even apply).
Then there is the fact that the trait doesn't apply at all on what are "ideal" environments for other bio pops, i.e. Gaia, Ecumenopolis and Ringworld (and also Hive World?). By design it seems to be a trait that gives a decent benefit early on but decays to near-irrelevance or even a minor nuisance in the mid-game.
It's supposedly refreshed in the mid-game by Hydrocentric, but honestly by the time you are terraforming planets, the actual bonuses granted by Aquatic are not that significant and you're mainly just coping with your species' eccentricities rather than making strong planets; it compares unfavourably to having a completely generic mix of species and just spamming Gaias with World Shaper, itself a fairly mediocre AP. The deluge Colossus is a nice meme when playing a genocidal empire, but with anyone else I don't think I would use it much, since it's better to make use of conquered pops if you can.
The Aquatic trait wants you to go for ocean worlds, especially early, it gives you a 20% output to minerals/food/energy and a +10% output to specialists on those worlds, you are forgetting about the 20% habitability which is massive at the start of the game.
You can't pick Ocean Paradise without going Aquatic which means you are losing 2 ocean worlds, which means Ocean Paradise isn't just worse than lost colony its worse than all origins which give you 2 extra Ocean worlds.
3 Ocean worlds are always going to be better than 1 Ocean world, the buffs are just not going to make up for the fact that for 1 trait point you are starting the game with 3 100% habitable planets.