I wish one of the objectives in Sword Base (Reach) was out on the lake and only accessible by speedboat. That would have been fun, riding out on the lake, dodging Banshee strafes and Wraith mortars.

: Hang on, shouldn't Scorpions be amphibious?

Only if they're riding a frog.

: I notice that your Selkie didn't have Elites on bendy poles with plasma
: swords. I see that as a design flaw.

That's more of a Brute thing. And Brutes are too heavy for the bendy poles, so they stick to jump packs.
Jackals on the other hand, are bendy-pole extraordinaires.