i vote for keeping the Reactor Heat Control; because it makes a good emergency cooling system.
Now that there isn't true Causac's the need for emergency cooling isn't as great (reactor components come into it allot more).
thoughts : cooling with ice/water was too easy, creating a super-explody-causac, or a simple+stable reactor with little inbetween; the idea of just cooling cooling cells i think is a good one, because they are potentially consumable, so if thigns go wrong, they can still go badly wrong with a poor design.
as for cooling with water vs lapis -- it depends on if you want to cool with a renewable resource or not. I would be in favor of not cooling with water, as that requires no effort to create. Ice,
creating lapis from uumatter is about 76k eu per lapis (assuming scrap), and you get 40k cooling from it. Everything produces more heat than EU, so it is a net energy loss to cool a reactor with UU constructed lapis. the same is for redstone (10k cooling from 28k EU spent).
twice compressed water->ice takes 1600 eu (standard compressor, worse with overclocking), or around 300 eu (advanced machines, fully spun up, and overclocked)
asuming that you can get snow for free, and have fully spun up advanced machine, the cheapest EU cost ice is about 150, so getting 100 cooling from ice is a net EU loss, if you used any machines in its making. - you gain, if you you silk-touched the ice, but you spent XP, and time to do that ...
An old causac could be cooled by 7 bocks/second to generate 2k eu/tick.
I am not against keeping ice as a cooling agent, because high power reactors create allot more heat than EU (4 Adjacent quad cell = 140 eu/t, 448 heat/second).
A new reactor with mostly double cells to generate 2k/tick generates over 5k heat/second - that would be 53 blocks a second. given that a fully spun up singularity compressor generates 2 blocks/second, the industrial requirements to actually do a full causac are very high.
I vote for leaving water and ice in at their current cooling levels, because the new reactor structure makes it harder to cool via this mechanism.
Regards,
Andrew