I have actually always thought IC2 nuclear output to be too low compared with other EU/t generation options especially when you take into consideration cost/complexity. I tend to avoid it in packs I play as I find scaled early game power gen (charcoal farm) good enough.
In my opinion, maybe a slight nerf to coal farm and a buff to serious buff to nuclear. Maybe disable the liquid boilers... creosote becomes useless as a fuel making the draw/efficiency of a tree farm less. Sort of the same reason why lava is not a valid fuel source in liquid railcraft boilers.
Really, for this pack, all things that can consume steam to create EU should do so at the same steam unit per eu/t generation ratio; assuming 100% efficiency. The upgraded generators are simultaneously more efficient and capable of outputting more max power making them worthwhile to get. To make things like nuclear more attractive given that standardization, nuclear steam unit creation rate should be buffed. Basically, allow more steam consuming turbines to use the same nuclear reactor. More steam -> more turbines -> more EU/t per reactor. In this way, the transition to nuclear is worth the cost as the scale required to rival that of a boiler farm is drastic. Something like, 1 nuclear reactor can replace 20 full sized LP boilers and without creosote, that would be one serious undertaking.
I also think, in this pack, all powergen that is not steam/fusion based should be disabled. So, no direct power from bigreactors, need the liquid IC2 reactor instead of the standard one, etc.
However, I also think that big reactors went too far on the output side of things. Given the conversion required to make that power useful however, I am ok with it.
CAVEAT:
I haven't played this pack much and some of the above my already be in place.