I would think that the Gemara's question is not trying to present an alternate reading of Rav Yehuda's statement, but merely asking as an aside that we should not say the Berachah of she'Asah Nisim all eight days. However, Rashi (DH "Kol Yomei") clearly contrasts she'Asah Nisim versus Shehecheyanu.

Therefore, it is possible that the Gemara's question is based on the understanding that all eight days were equally miraculous (according to the explanation that each day used one eighth of the oil). If this is so, one could suggest that the Berachah of Shehecheyanu should be recited every single day for the new miracle which occured each day, while the Berachah of she'Asah Nisim is made on the type of miracle. Being that the same type of miracle occured for eight days, one would only need to make the Berachah the first night. This is why Rashi (ibid.) explains the Gemara's answer as "[there was a miracle] every day - that all eight days they lit from the jug, but regarding Shehecheyanu when we arrive at the beginning of the time period, we have already arrived." Rashi seems to be explaining that the Berachah of she'Asah Nisim is not a Berachah on the type of miracle, but on its occurence, and hence we make a Berachah every day. Shehecheyanu is a Berachah on arriving at a time marked by miracles, and therefore it is only fit to recite Shehecheyanu once we have arrived at that special time period, not constantly within the eight days of miracles (alternatively, see Chidushei Chasam Sofer at length).

All the best,

Yaakov Montrose