Kayneth was a brilliant magus, I can not debate that. He was the head of a prominent family, dual wind and water affinity, summoner, alchemist, and specializing in the control of mercury--a weapon called 'Volumen Hydragyrum'.

It's simple fact that he was a genius among magi, and in that respect alone I had an excellent Master.

Similarly, had he but taken a moment to comprehend that others--particularly Kiritsugu Emiya--would decide to wage the Holy Grail War in a manner not fitting of a traditional magus... I imagine we both could have survived it. Had he for even a second focused less on mistrusting me and more on analyzing an enemy he thought beneath him...I'm certain I could have won the Fourth Holy Grail War.