no one here has said that his 1500m times are impressive. what they have said is that it is impressive that he has improved by 8 seconds in the fifteen this year and that this improvement indicates significantly better aerobic conditioning this year in comparison to last year when he ran 1:44.7 (which, by the way is 1 s under the A standard per 800m and thus probably worth 3:34). The 800 is supposed to be fifty/fifty anaerobic/aerobic or maybe even more aerobic than that, so the aerobic improvements should pay dividends, as will an added year's physical maturity, training, and experience.