What makes an opamp "high-speed"?
The UA715 opamp was and still is high speed, because of the precision settling achievable. Why is such settling possible? Because the opamp silicon designers implemented (1) low input capacitance, using cascading of the input diffpair; low Cin preserves the basic opamp loop dynamics even with large resistor values; (2) widened the linear range of the input diffpair, using emitter degeneration, thus the opamp changes from high-speed-slewing into the needed linear-response-settling while still a large input error exists between Vin+ and Vin-.