Stronger player loses "deuce". Weaker player is now returning from the "ad" side and therefore the game is lost.
Compared to...
Weaker player loses the deuce. Stronger player is now returning with a score of ad-out. You're still in the game.
How is that any worse than strong player loses ad, game over? And think about the situation where the serving team has had two or three ad points that the strong returner has fought off. Eventually, they're going to just start going for more on that side like trying a planned poach, going for two first serves, or just go for bigger shots all-round. After all, they've got nothing to lose when they're ahead in the score.
If they're always behind in the score against the weak player, they're not so likely to take such risks because they do have something to lose in that situation.
It's completely anecdotal, which is my point. I could say that people love to serve aces out wide, and since even the stronger player cant return those aces, the stronger player should therefore play deuce so they can get in more points. It's a custom scenario, not a standard situation.
At what point does it stop being anecdotal? I see it play out with quite a few different players, so at what point can I admit there's a trend?
And I could say that serving a kick serve out wide on the ad side is much easier to hit vs. a kick serve down the middle. This means that if the weaker player plays the ad side they will have to hit many more backhands than if they return on the deuce side. Sure, they may have an easier CC BH return, but they will have to hit the backhand much more often than on the deuce side even if they feed balls to the net guy. Also, I could also say that a BH DTL return from the deuce side is a very natural return. If a net player is super aggressive at failed IO-BH's, you can burn them DTL which is a much more natural shot.
How is a kick down the middle more difficult than out wide? If you're playing against someone who can't figure out that serving from really wide on the deuce side limits their options to hit down the middle, then you don't have much to worry about in general.
But, if you do play someone with a kick serve who is smart enough not to stand way out by the singles line, then hitting an inside-out backhand from the deuce side against the kicker is more difficult for most people than crosscourt from the ad side. Neither is an easy shot, but one is more difficult than the other.
Also, a very situational argument. What if I said that I only serve second serves to the weak player, regardless of the score? But, against the stronger player I will serve big on both serves, especially on scores where we are winning or losing by a lot? None of those things has to do with which side either of the players are playing, EXCEPT that we're more likely to see the Ad-side player during an game point.
If you're completely disregarding the score on every point on serve, then it still makes sense to have the strong player on the deuce side, because those important game points on the ad side will more likely be break points if the strong player is on deuce than if the weaker player is. And as I've said before, you can't break serve without break points.
Again, this is completely situational. This "insane serve return lobber" can also hit those lobs from the deuce side. I'd rather have that on the deuce side since it's not likely game point. I dont want someone hitting a lob return on a game point. How can you expect to win points when the first "ground stroke" your opponents hit is an OH? Even if it is at the baseline after the bounce?
I can't really understand what point you're trying to make with lobs. It seemed that you suggested lobs as an alternative shot for someone with a weak return, as if they can consistently hit good lobs off of serves. Now you seem to be admitting that lobs from a weak player would result in a lot of overheads for the serving team (i.e., the weak player can't hit consistently good lobs from serves).
The only thing I can understand is the hypothetical situation where the serving team is hitting a lob. But that isn't going to happen unless the returning team either hits a good lob down the line or the server stays back and sees the returner hit a good return and come to the net (and even then, the server might not lob). I don't think either happens often enough to be a determining factor when it comes to choosing sides.
In the "ideal world" the stronger player plays ad side. This is why a great majority of professional mixed doubles combos use the man on the ad side and not the woman. This isnt "psychology" or "custom scenarios". It's simple tactics, and statistically the ad-side of the court sees many more game points than the deuce side. The men play ad side in mixed so they can hit OH's in the middle and return a majority of game points. Even in Hopman Cup which is no-ad scoring and "same gender" returns at deuce, you still have the men playing the ad side a majority of the time, just because having the OH's and protecting the middle is the biggest responsibility.
And how often do things change in tennis? People used to hit flat, continental forehands for decades, but now they don't. People used to play serve and volley for decades, and now they don't. People used to play rightie-leftie on deuce and ad, but the most successful doubles pair in all of history plays the other way around. Maybe people keep playing that way because they've been told to play that way by people who themselves were told to play that way. Some people just never question their coaching.
I know I always followed the traditional wisdom until I realized that, for me personally at least, the other way around works better. I win more often when I'm setting up break points for my partner over and over than when I'm clawing games back to deuce over and over.