I don't know if it's the case for many comic book stores but mine doesn't seem to sell many copies (if any) of Superman and Wonder Woman. Recently I saw the trade for the 75th anniversary of Lois Lane and it made me think why I can't see the romance with Diana ever working. Why do some want it in the first place and why is the relationship seen in a negative light?
Just a few thoughts on the subject.
There's a lot of emphasis on power for the new couple. Let's be honest here, why do many in favor of the pairing want it to exist? You see the argument all the time on message boards usually whenever Diana's love life is mentioned. She "needs" a guy with power to be her equal? Why? There's never as much outcry for Clark or any other superpower male to date a woman with power as there is for Woman Wonder to find such a man. When you start to think about the reasoning behind that what's between the lines is very uncomfortable. Is it because Diana, the ultimate female superhero, can't be more powerful than a male lover? Why not? Because it might cast too big a shadow on him and he may be put in the dude in distress role?
From what I've seen the reasoning for Superman "needing" a powerful lover is more, er, intimate. Something more in line with Frank Miller's Dark Knight Returns sequel. These reasons basically say that the woman in the relationship can't be more physically powerful than the man and in order to fulfill him sexually needs to be "less frail" than a normal woman. But much like Frank Miller's portrayal of the two as a couple this often brings another knock to Wonder Woman as she's often shown as the lesser of the two. Whether in combat, being less level headed or in some truly out of character moments that don't paint her in the best of light. Again Miller but there are others,
That's not to say others haven't written her badly when their not a couple. Geoff Johns, while a talented writer doesn't seem to get Diana's character. She's usually bossy, more blood thirsty than Superman/Batman and someone that's a little too perfect. The message usually coming across that she needs to learn humility and understand humanity better. Which isn't what she's about at all. Diana is compassionate but just because she sees death as a potential ends to a conflict doesn't mean she lacks empathy nor her links to the Amazons/Greek Gods mean she thinks she's better than others. She certainly doesn't need to learn this from Clark anymore than he needs to learn about humans from Batman. They just see thing differently. Which might bring a obvious divide in the romance in the future.
Clark and Diana may have similar goals and outlooks but their morals are too different. Superman is supposed to be idealist and that should cause conflict with Diana in dire situations. Take for example the Max Lord situation which many have debated to death. Superman wanted Max to live but while under the influence of the lasso of truth Max confessed he'd never stop trying to control Superman for his own agenda. That the only way he would cease was if he was dead. That sort of conflict might mend in a friendship but in a relationship it would wear thin over time.
Interesting enough Diana represents truth something that's also seen in Superman lore via Lois Lane. While you can make a case for Clark, the Kents and even some Daily Planet reporters no one searches for it as tirelessly as Lois. While she could have some advantages as Superman's lover in general she's out in the field risking her life knowing she could die at any moment. That's how much she values what she does. To Lois it's never a question if it's worth it because in her mind it always is. The Kents may of given Superman his humanity and values but Lois reminds him of them. She's his anchor and proof of what we're all capable of. Lois is amazing because she's a human that accomplishes incredible things and does it for the right reasons. That's pretty damn impressive and inspiring.
Not to say Diana isn't impressive or inspiring on her own but she isn't meant for Clark. Lois is. Making Diana a placeholder for such an epic love is a insult to the character.