I dislike most of these suggestions (and I dislike the attitude with which they have been presented). Originally put a downvote on the OP but it may as well be a counterargument I suppose.
In general I think it is not worth making people memorize new icons unless there is a clear necessity for it. The Dagger/Bolas change still confuses me sometimes.
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Cyclops: I would describe the thing which unifies the fire-support units as "is like a skirmisher but less self-sufficient, particularly considering the case where it needs to move". Cyclops doesn't really fit that criteria. Skirmisher isn't the best category for it either, but I would prefer to see it given a unique super-heavy-assault icon rather than fire support.
[Spoiler]The fire support units also generally have a fairly flat firing trajectory compared to artillery (which is conveyed by the icon perhaps). I suppose this is why Lance has the fire support icon. Bulkhead blurs the line but doesn't really have the range to justify being called artillery.
Venom: Is sort of a dedicated anti-raider like Bolas and Archer, but gets used even less in classic raider roles than either of those two units. If it had the raider icon already I would not change it to riot, but I don't think it needs to be changed to raider either. Calling even the current state of Venom a "special riot" is not misleading.
Amph: The icon shapes are nominally based on whether the unit surfaces to fire or not. Scallop's icon is outdated and possibly should be fixed. I have never had much difficulty telling Duck and Archer apart, though. Duck could move to a scout icon if it really needs to I guess.
I think Lobster looks better as it is than it would with a star or transport symbol (both of which are taken by Limpet and Djinn anyway). Maybe it could have something unique (perhaps an arrow pointing diagonally upwards by analogy with Newton?).
Gunships: I think the two different base icons to represent light/heavy gunships is fine.
Planes: Fighters have a very different role to bombers, and both are important to keep track of, so I think it is desirable for fighters to have a unique icon design. I think Phoenix and Thunderbird icons are close enough to accurate to not be worth messing with. I also can't comment on the zero reason provided for disliking Sparrow.
Scorpion: All of the strider units are "special" in some way or another. I think there's a case for distinguishing the icons of Scorpion and Paladin, but putting a star on Scorpion just moves it closer to Funnelweb. Maybe Funnelweb should change to account for its new role I guess.