To point 1, I think the more I think about it, the more I feel Aquatism had proven this to not be as much of an issue than y'all think it is, though I could be wrong. Without any level of A/B testing, though, I'm not particularly convinced y'all have enough data. This is doubly so given the amount of popularity towards more "blue land" suggestions from admittedly the vocal minority
To point 2... I feel like naval would be perfectly viable even with tier 2 ports. This seems like an incredibly weak argument, particularly when look at what has actually been seen in practice. If anything, moving ports tier 1 has had the opposite effect: before both land and water combat was viable on continents maps. Nowadays, players treat it as basically a given that continents is a water map. The gatekeeping was 100% necessary, and if this is the design you want to push, there needs to be actual nerfs to the units of the tree, not the pop