Hard disagree.
Two multi platform games not synonymous with Sega aren't more important then Virtua Fighter on a Sega console.
If we were talking about a spiritual successor to the Saturn, then not having Virtua Fighter (or Sega Rally) would disqualify you immediately, because those game define the system to a great extent. For the Dreamcast however Virtua Fighter 3tb was rendered obsolete by Soul Calibur before the US release was upon us. The DC isn't remotely defined by Virtua Fighter (or the poor port of Sega Rally 2).
Dead or Alive 2 on the other hand was a huge deal on Dreamcast. Dead or Alive 3 and Dead or Alive Ultimate were also not multiplatform. They were Xbox exclusives.
Third party games absolutely can be more important to a console's legacy than first party output. Metal Gear Solid, Tomb Raider and Final Fantasy VII are more important to the PS1 legacy than the cast majority of Sony's own output, and if a following console then had sequels to each of them, they would absolutely be more of a spiritual successor than another that just had Twisted Metal instead.
Even a Power Stone followup would mean more to a platforms Dreamcast-like qualities than Virtua Fighter would. Virtua Fighter is a Saturn defining IP that just happens to have a Dreamcast entry, much like how Shinobi X isn't meaningful to Saturn the way Revenge of Shinobi is the Genesis/Mega Drive.
We're not discussing games synonymous with Sega. We're discussing games synonymous with
Dreamcast, and in that conversation Virtua Fighter doesn't rank very highly at all.