I think it is very difficult to guess how questions of this sort play out in the CoP. For instance, I would expect that if Yu-na replaces 3Lz+3T and 2A with 2A+3T and 3Lz, then her scores in Interpretation, Transitions, etc. will go down, not to mention the GOE on her step sequence. The judges will say, Yu-na regressed from last year, she's not the skater she once was.
Yu-Na is not replacing her 3Lz/3T, which is her hardest and most consistent element, and it'll be the hardest combination with the greatest chance of success of any of the podium contenders (Miki hasn't had any 3/3s ratified this season, and Mao and Rachael haven't attempted any that I can recall), so I don't see this scenario happening. Now, you may have a point that PCS has an unofficial relation to technical content (hence a men's skater with superb components but doesn't have a 3A is penalized via PCS), but that doesn't apply here when Yu-Na is still keeping her 3/3 and very few of the top ladies have gotten anything beyond a 2A/3T or a 3T/3T ratified this season.
Case in point: last year, as long as she landed that 3Lz+3T she always got great GOEs on her ordinary-at-best spiral sequence.
The execution of Yu-Na's 3/3 has never had anything to do with the GOE she got on her "ordinary-at-best" spiral sequence, or any of her other elements. Case in point, Yu-Na's 2007 Worlds SP, which set a world record and received a +2.00 in GOE for her 3F/3T...but a mere 0.43 in GOE for her spiral sequence. Which was fair because her spiral sequence as executed was shaky and her injuries and conditioning that season had significantly affected her extension (and thus was reflected in the relatively low GOE that she got on that element all during 2006-2007).
The next season, healthy, she really worked on her extension and improved the spiral sequence, and it showed--and her GOE went up from the season before, even when she missed her 3/3 as she did at the 2007 Cup of China SP and the 2007 GPF SP. By 2008 Cup of China, she hit her peak GOE for the spiral at +2.00 and it remained a strong element for her since then as opposed to a weak one in 2006.
There are many skaters who have "ordinary-at-best" spiral sequences (if you judge strictly based on extension) and received high GOE for them, and they did not have a 3Lz/3T that Yu-Na did. See Joannie Rochette in the Olympics SP, Laura Lepisto and Miki Ando at the Olympics LP; Miki Ando at the 2011 4CCs LP where she received the same GOE as Mao Asada for the choreographed spiral sequence. This is a reflection of the rules system that awards GOE based on a number of qualities that aren't limited to extension, and all of those skaters fulfill the criteria for it in different ways.
If you think the system should be changed to focus more on position than any other qualities of a spiral, okay, but that is a separate argument, and has nothing to do with Yu-Na's GOE. Btw, she did not get the highest GOE on spirals or footwork at the Olympics; Mao did. And Mao, despite not completing any 3/3 or any 3A attempt, still received the highest GOE for her footwork at 2010 TEB, so again, I don't see why GOE for non-jump elements should go up or down depending on what jumps are executed. Many more examples like this exist.