Well it's not happening so I guess we don't even need to go there. Jarmila K was the WR holder in the 400m at 47.99 - from blocks. Never really touched the 1500m so we don't know but it's kind of irrelevant because she did run 1.53.28 - the WR.
Mu's profile right now is 49.57, 1.54.97 and 4.03.44. Is the 400m really getting much better - especially now with an obvious shift to the 800/1500 side? (she didn't even clock an official 400 in 2023 and in 2022 ran 50.4). Let's give her the massive benefit of the doubt and say she can get to 49.0. But that is not enough to run in the low 1.53's so she is going to have to at the same time pull her 1500m time down into the 3.59/4.00 territory at a bare minimum.
Now we see the conundrum - improve your 400m speed (and 0.6 is a considerable chunk) and your 1500m endurance (enough to take 3+ seconds off a time which I think was a stunning performance for her to begin with) concurrently. Just don't see it happening. If Mu got down into the low 1.54's it would be awesome and let's be honest that is not a slight on her because it would 100% be the WR as our only 2 times under 1.54 are absolutely PED aided and Semenya and Jelimo were by todays precedent not going to be eligible to compete in the womens category (Jelimo I think as well on some special vitamins).
Back to Keeley H - good time and good start to the season but I really believe that if she wants to maximize her talent, that 1500m needs to dramatically improve. Clearly she sees herself as a pure 400/800m runner but we now know how important the over-distances are for any MD event - a 56.0 first lap for her now is no problem as a 51.5 runner - but can she follow that up with a 58.5 is her challenge and that strength lies in the 1500m and not in the 400.