actually i find both the ceiling figure and the takeoff figure quite good, there arent many planes in the same class surpassing those figures. 350 meters would be a light load, 650 meters a heavy one, thats very comparable to the likes of eurocanards, f15, su27, etc. Same goes for 18.000 meter ceiling, thats quite a bit. Combat ceiling is always gonna be less, anyway, and it doesnt scale linearly with the max ceiling.
Mach 2 speed is perhaps a tad underperforming, but then again, there arent many one engined designes going faster. Plus, it goes in line with the decision to use a DS inlet in j10b, which, as we are often told, has a practical usage limit at around mach 2.
Takeoff weight is also very comparable to f16C models, and higher than, say, Gripen.
Quoted length is, i believe, with the nose probe, right?