HARMs were both OP and not fun to play against. Nothing in Cybran roster relies on HARMs as some fulcrum for their naval gameplay. If you were reliant on it, it's because you were abusing a gimped unit rather than playing the perfectly functional Cybran navy. As a sentoner, you should be aware that there were a decent portion of high level sentoners that made house rules to just not use HARMs because of this, including Yudi.
Hives were likewise not ruined. By ruined you mean they were brought down to the statline of UEF kennels. Costs UEF like 25 mass per unit of BP in a kennel, costs Cybran like 18 mass per unit of BP in the first stage of hive. Hives carry more general utility via instant transfer across projects compared to kennels which have innate lag and can be interacted with by units like aa or interceptors. So even if they were equal in mass per BP, hives would still be better in most situations.
For laser:
let's say you have Aeon T2 PD and you're playing a Cybran that has no vet. You have 4 seconds before a Cybran ACU kills you. Oblivions fire every 4 seconds. This means you need 17 Oblivions to be in range to kill the Cybran ACU before you die assuming no stationary shields. But people will make survivability upgrades. Let's give the Aeon ACU 19000 more HP. Now you have 10 seconds. That means you only need to make 9 Oblivion turrets. That's approximately, at an utter minimum, 10k mass in t2 PD and I think another 3kish in ACU upgrades? Now put that across 4 slots, and you have around 52k mass in defenses. None of this is possible to make as a response late game btw, it just needs to exist on the sheer reality that Cybran exists. It also doesn't factor in that any map beyond dual gap, you have an air grid away from SMD away from potentially ACU away from large mex expansions which can all be teleported for value.
That's for an upgrade costing 15k mass, btw. Of course the cost of tele is inherently more focused on E, but at min 28 you can have the 5 t3 pgens to make it in 2 minutes basically anywhere, especially sentons.
Playing random faction is basically universal at 1800+, I can think of like 3 examples where it isn't true and 2 are Cybran players. I imagine at sentons, nearly everyone 1500+ also plays random just because it's established as the norm in that community in the first place.