Even with the spawn rates turned up, I find the game becomes terribly simply terribly quickly. Once the player has gathered a suitable set of basic tools or attained even a minimal amount of mobility the game devolves into sandbox-mode. Scent is an excellent mechanic, but I would suggest greater persistence with respect to player-scent. At present, there is nothing to prevent the player from stockpiling food and shutting themselves in for days at a time, honing skills and fortifying positions.
Alternate proposal: The longer a player spends within a certain radius, the higher the spawn rate rises, regardless of noise generated.