I don’t doubt that there are better phono stages than the Urika. In fact, it wouldn’t be at all surprising if Linn were to upgrade the analogue amplification part of their phono stages along with the Ekos SE as you suggest. I recently heard someone from Linn say that they anticipate a series of LP12 related upgrades in future.
However, what they have clearly demonstated with the Urika II is that it is beneficial to carry out RIAA processing in the digital domain, particularly with the improved clock of the Klimax DSM/3. That’s basically the reason why I returned to vinyl after a break of five years.
Of course, whether the improvement from thus reducing noise, interference and distortion in the RIAA processing, pre-amplification and also potentially the crossovers with Exakt, not to mention Space Optimisation, is worth the lack of flexibility to use other manufacturers’ components is entirely a matter of personal preference.