A seven year contract will end when Plek is around 34-35 and he's a lesser player than Savard. I know the situations aren't exactly the same but you can draw comparison IMO. Both are small centers and playmakers. Savard is older but way more proven. I feel Savard's contract will be used as a comparison among other factors.
Savard is better offensively easily. Plekanec is better in every other situation. If Gomez and Gionta are getting 7.4 and 5 each per year(and people here actually defend that like is not bad for some reason), Plekanec deserves every bit of 4 per year. Even at the same contract i would take Plekanec over Gomez or Gionta, he is more important to this team.