Yeah, but the game was intended for 4:3 displays, so couldn't you argue this is actually the proper presentation for it? Chrono Trigger is one of the examples people point to as evidence that these games weren't meant to be displayed at 8:7.... so I dunno. I'd think another Square game from 1995 would probably be the same deal.
First point :
This is a false argument in my opinion. The vast majority of SNES games were not designed with the fact that the picture was stretched from 8/7 to 4/3. All these games have circles that are actually rendered as ovals. And this is perfectly understandable, from a developer point of view, what are your choices when working on SNES ?
If your sprites are rather small, and their basis is 16x16 tiles, what can you do ? The console does not offer you 14*16 tiles to begin with. So you work in 16*16 but always leave two columns blank ? This is a hassle, and not the solution that was used in the vast majority of the games. You can eventually begin to think with stretching in mind when you have big sprites, which did happen in a few fighting games. I am pretty sure that Mortal Kombat II does this, which is pretty clever from the developers. But that's an exception, not the norm. Also games were necessarily displayed on 4/3 screens, this does not mean that every SNES game was designed with stretching in mind.
Seiken 3 clearly has wide characters and ovals everywhere in the game. It would be look better in 8/7.
Second point :
Even if the graphics are stretched, our CRT TVs could display rectangle pixels without a problem. In fact, the vertical resolution is always adapted to fill the entire space. You even have games that are actually squeezed to fit because the resolution is wider than 4/3 (CPS 2 games from Capcom, and these were definitely created with this is mind). And that's the magic of the CRT TVs.
Our HD TVs don't do this. You have a set number of square pixels to display your stuff. Meaning that stretching from 8/7 to 4/3 on an HD TV means that some pixels are going to be doubled, some won't. In this situation, as the resolution is multiplied, you get stuff like 5*5, 5*4, 4*5 and 4*4 pixels. This is uneven and definitely not a good effect. This kind of display also make applying scanlines impossible without creating ugly patterns on the screen. Maybe that 4K TV will enable stretching from 8/7 to 4/3 perfectly, I haven't done the math yet.
This is a common issue with 8/7 content. It also applies to NES, Master System, PCE and some MegaDrive/Mega-CD games. And developers doing emulation stuff rarely nail these problems down, even with 4/3 content to begin with.
And about Chrono Trigger, in my memories sprites are a bit thinner so this one was probably done with the intention of using the 4/3 stretching. But in the end, it is a matter of preferences, it is not the norm for SNES games, and the problems listed previously still apply.