It is pretty simple, IMO. Long hood, shorter rear trunklid and short overhangs are a classic combination that generally always looks good. TLX does this very well for a FWD car, compared to the ES which has more classic FWD proportions with a longer front overhang, shorter hood and longer rear trunklid. TLX looks more like a performance car for this reason, though I doubt even 95% of buyers look at this or care.
I know that this forum loves to dump on Acura, but the proportions of the TLX are vastly better than the ES, and even the LS, which also has an awkwardly long front overhang for a RWD car.
Anyway, hopefully this is something Lexus plans to remedy going forward. 2021 IS was a step in the right direction, and this concept looks great.
While the LS front overhang is certainly ungainly, I respectfully disagree with the TLX and ES. The TLX still has a large front overhang, that is masked by the silhouette and profile. The ES in real life looks quite good proportionally speaking and the front overhang does not look that ungainly or odd like the LS. Could the ES front overhang be better? Of course, just like the TLX and LS front overhangs could be a lot better. The LS is the biggest offender as it's RWD. It has no excuses.