I agree that fixers don't have any NCU problem when playing alone, yet NCU can be filled up fast with buffs from other profs in teams or in BS.
In my current setup I have 316 NCU (816 when buffed), and the self buffs take up 425/816 (fixer buffs take 390 as I listed in a previous post, plus Defensive Stance takes 1, Lesser Deflection Shield (Extended) takes 10 and 6 common composites take 24). It is not uncommon for fixers to fill up their belt slots with junk (which are quite useful most of the time), so I'll use this NCU setup to illustrate a common pvp scenario. (The numbers inside parenthesis are NCU costs of respective nanos)
Current Fixer vs fixer PvP:
In fixer vs fixer combat it's not unusual to spam Program Override, however it rarely lands since it's checked against 200% nano resist.
PO removes these nanos:
Greater Preservation Matrix - 30
Experienced Survivor - 20
Embrace of Shadows - 9
Firewalled Sync Compressor - 2
Blessed By Shadow - 2
Defensive Stance - 1
Lesser Deflection Shield (Extended) - 10
and at least 3 of the composites - 12
NCU usage after PO: 351/316
Fixer A can counter this temporary nerf by swapping Infused Viral Compiler with Memory NCU (6/6) in about 2-3 seconds as they can not be swapped from toolbar and it has to be done manually. After the swap, Fixer A gets 351/508 NCU, which makes it possible to recast Defensive Stance, Greater Preservation Matrix, Firewalled Sync Compressor and the rest of the buffs. But then, if Fixer B uses NCU HAXX (Hacker's Signet of The Apocalypse), NCU of Fixer A gets nerfed down to 351/208 for 15 seconds, and gives Fixer B the opportunity to do at least 1 FA and 1 AS.
At this point Fixer A has to free up 145 NCU in order to perk Defensive Stance (1) and cast Firewalled Sync Compressor (1)
If he chooses to remove Karma Harvest (47), Blood Makes Noise (36), Improved Frenzy of Shells (56), and the remaining composites (12), Fixer A's NCU usage becomes 200/208 and then he can perk aad and cast the NCU buff.
Alternatively, he may choose to free up 174 NCU in order to perk Defensive Stance (1) and cast Greater Preservation Matrix (30) before anything else, so he can also remove Improved Semi-Sentient Augmentation Cloud (40) and have 160/208 NCU.
Also, he can swap another deck (which takes 10.5 seconds due to high equip delays of deck items that he wears) and get 351/400 NCU, which allows Fixer A to cast long hot without removing running buffs in his NCU.
After rebalance:
The same buffs will take up 540/818 because NCU cost of Lesser Deflection Shield (Extended) will be increased from 10 to 29 besides the increase in NCU costs of fixer buffs. Moreover, PO will land more often since it will be countered with 50% nano resist.
PO will remove these nanos:
Recoded Preservation Matrix - 35
Experienced Survivor - 20
Embrace of Shadows - 9
Firewalled Sync Compressor - 1
Defensive Stance - 1
Lesser Deflection Shield (Extended) - 29
and at least 3 of the composites - 12
NCU usage after PO: 783/316 for 10 seconds, then 433/316
At this point, Fixer A may swap decks (as described above) to get 783/508 NCU, but it's still not enough to cast anything for 10 seconds until c0mP0s1t3 477r1bu73z b00s7 and c0mP0s1t3 n4n0 3xp3r71z3 wear off. At the 10th second, Fixer B may use NCU HAXX to nerf NCU of Fixer A to 433/208 for 15 seconds.
In this situation, Fixer A has to free up 227 NCU to cast NCU buff and perk aad. Before the rebalance, he was able to free up his NCU by removing less useful nanos, and nanos that don't buff his defenses (Improved Frenzy of Shells, composites). This time however, he has to remove more useful buffs since perception modifier of Karma Harvest (47) is added to Blood Makes Noise (36) and root and snare resist modifiers of Firewalled Sync Compressor (1) are moved into a new nano (Preserve Movement - 40)
Also, he has to free up 261 NCU if he chooses to perk aad and cast long hot before casting anything else. (Notice the increased NCU cost of long hot in the rebalance!)
Alternatively, Fixer A can swap another deck to get 433/400 NCU and cast.. oh wait, he can't cast anything even if the swaps 2 decks
Conclusion:
If total NCU usage stays the same after the rebalance, Fixer A will be able to swap 2 decks in 12-13 seconds while waiting for PO debuffs to wear off and start buffing after 15 seconds with 351/400 NCU without removing anything from his NCU.
Currently, the NCU debuff combo rarely happens and lasts for 10 seconds. It can be dealt with swapping and removing a few less useful nanos. However, if NCU requirements increase and PO lands more often, the debuff will last 25 seconds and it will extremely difficult to deal with.
As a final note, I didn't include buffs from other profs and LE proc hots and evades, but I can only assume that filling the entire NCU with buffs from other profs will make it even worse for fixers after the rebalance as it will require more effort to free up NCU.